Apparatus and method for writing and reproducing data

ABSTRACT

High-rate writing of data recorded on a CD into a hard disk drive (HDD) is performed while reproducing data read out of the CD at the standard bit rate prescribed for the CD. PCM data corresponding to a playback time of 10 seconds, for example, is read out of a CD and stored in a memory. The data is read out of the memory at appropriate timing and outputted after being converted into an analog audio signal by a D/A converter. In parallel, data for writing is read out of the CD in succession to reading of the data for playback and stored in the memory. The data read out of the memory is coded and compressed by an encoder and then stored in the memory. The compressed data is read out of the memory in units of a certain amount suitable for writing in an HDD and then written in the HDD. When the data stored in the memory for playback has become smaller than a predetermined amount, an interrupt is generated during the writing process with the processing, which is given top priority, so that a next set of playback data is read out of the CD and stored in the memory.

This application is a countinuation of application Ser. No. 09/697,917filed Oct. 27, 2000 now U.S. Pat. No. 7,126,770.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a data writing and reproducingapparatus and method for transferring and storing audio data, which iswritten in a removable recording medium such as a music CD (CompactDisc), in a built-in storage medium at a higher data rate than the rateprescribed for playback of the music CD.

2. Description of the Related Art

A so-called CD changer containing many CDs and automatically reproducingaudio data recorded on the CDs is well known. In such a CD changer,several tens to several hundreds of CDs are contained in one housing,and one of the CDs is selected with a predetermined operation forautomatic playback. Audio data recorded on the CDs can be reproducedorderly for each of the CDs or at random, in units of one CD or onepiece of music recorded on each CD, by selecting a plurality of CDs.That type of CD changer is mostly employed in stationary fashion, thatis, by being installed in a room.

The above-described CD changer, however, had a difficulty in realizingcontinuous playback because a CD exchange time was required even in theautomatic playback mode. Also, a CD changer containing 100, 200 or moreCDs was very inconvenient to carry and install in place because of theincreased size and weight of the housing.

To overcome those problems, instead of the CD changer, there has beenproposed an audio server employing a storage medium, such as a hard diskdrive, which is relatively small in size, but has a large storagecapacity. In the audio server, audio data recorded on each CD is read,and the read-out audio data is coded and compressed by a predeterminedmethod. The compressed data is written and stored in the hard diskdrive. By using a hard disk drive having a storage capacity on the orderof 6 GByte, data of about 1000 pieces of music can be written. The audioserver is superior to the above-described CD changer in that continuousplayback can be easily realized because of not requiring exchanging CDsunlike the CD changer, and in that the housing size can be reduced eventhough a larger amount of music data can be written in one unit of thehard disk drive.

Further, in the audio server, when audio data recorded on a CD iswritten and stored in a hard disk drive, the audio data can be handledin the same manner as ordinary digital data. Accordingly, data can bewritten and stored in a shorter time than the playback time prescribedfor a musical composition or the like, which has been recorded on a CD,by rotating the CD at a higher speed than the standard rotational speedprescribed for the CD and thereby reading the data out of the CD at ahigher rate.

In the conventional audio server described above, however, during thetime in which audio data recorded on a CD is written and stored in ahard disk drive, the audio server is exclusively employed for theprocess of writing and storing the data. This has given rise to aproblem that the user has nothing to do other than just waiting untilthe writing process has ended.

For example, even when a 20×CD-ROM drive capable of rotating at anaverage rotational speed about 20 times as fast as the prescribed speedis employed for playback of a CD, about three minutes is required for aCD having a record time of 60 minutes until the writing process hasended. Such a waiting time makes the user feel irritated and impatient.

To avoid the above drawback, it has been proposed to provide a userinterface such as a certain display on an audio server. Even with theproposal, however, the user is obliged to wait until the end of thewriting process while viewing a message, for example, “Under Copying”,indicated on a screen of the display to inform the user of such a statethat the process of writing and storing the data is being executed,while hearing a beep or other like tones.

On the other hand, there has also been proposed a portable audio dataplayer using a hard disk drive or a semiconductor memory as a storage orrecording medium. The portable audio data player is connected to theabove-described audio server, and audio data stored in the audio serveris transferred to the portable audio data player and stored in thestorage or recording medium. Assuming that the storage or recordingmedium has a capacity on the order of 200 MB, for example, audio datacan be stored with a playback time of several tens of minutes.

When audio data is transferred from the audio server to the portableaudio data player in such a way, a similar problem as described abovehas also been experienced, that is to say, the user has to just waituntil the end of the data transfer.

SUMMARY OF THE INVENTION

An object of the present invention is therefore to provide an apparatusand method for writing and reproducing data, wherein, when audio datarecorded on a CD is played back to be recorded and stored in a built-inhard disk drive at a higher data rate than that prescribed for the CD,the audio data recorded on the CD can be written in the hard disk driveat a high data rate while the CD is being played back at the prescribedreference data rate.

To achieve the above object, according to a first aspect of the presentinvention, there is provided an apparatus for writing and reproducingdata comprising a processing unit for processing inputted data; astorage unit for storing the processed data in a storage medium; adecompression unit for decompressing processed data stored in thestorage medium; a reproducing unit for reproducing the decompresseddata; and a control unit for controlling the storage unit to store theprocessed data in the storage medium during reproduction of thedecompressed data by the reproducing unit.

Also, according to a second aspect of the present invention, there isprovided an apparatus for writing and reproducing data comprising aconverting unit for converting inputted compression data of a firstcompression format into data of a second compression format; anoutputting unit for outputting the converted data; a reproducing unitfor reproducing data corresponding to the converted data; and a controlunit for controlling the outputting unit to output the converted dataduring reproduction of the data by the reproducing unit.

According to a third aspect of the present invention, there is providedan apparatus for writing and reproducing data comprising a processingunit for processing inputted data as the need arises; an outputting unitfor outputting data supplied from the processing unit; a reproducingunit for reproducing the supplied data, and a control unit forcontrolling the outputting unit to output the supplied data duringreproduction of the supplied data by the reproducing unit.

According to a fourth aspect of the present invention, there is provideda method for writing and reproducing data comprising the steps ofprocessing inputted data; storing the processed data in a storagemedium; decompressing processed data stored in the storage medium;reproducing the decompressed data; and controlling storage of theprocessed data in the storage medium during reproduction of thedecompressed data.

According to a fifth aspect of the present invention, there is provideda method for writing and reproducing data comprising the steps ofconverting inputted compression data of a first compression format intodata of a second compression format; outputting the converted data;reproducing data corresponding to the converted data; and controllingthe output of the converted data during reproduction of the converteddata.

According to a sixth aspect of the present invention, there is provideda method for writing and reproducing data comprising the steps ofprocessing inputted data as the need arises; outputting data suppliedfrom the processing unit; reproducing the supplied data; controlling theoutput of the supplied data during reproducing the supplied data.

With the first and fourth aspects of the present invention as describedabove, inputted data is processed and stored in the storage medium. Thecontrol unit performs control such that the processed data is stored inthe storage medium while the processed data stored in the storage mediumis decompressed and reproduced. Therefore, the inputted data can bereproduced and, at the same time, stored in the storage medium.

With the second and fifth aspects of the present invention, inputtedcompression data is outputted after conversion of a compression format,and data corresponding to the converted data is reproduced. The controlunit performs control such that the converted data is outputted whiledata corresponding to the converted data is reproduced. Therefore, theinputted compression data can be outputted while the format conversionthereof is carried out.

With the third and sixth aspects of the present invention, inputted datais processed and outputted as the need arises, and the processed data isreproduced. The control unit performs control such that the processeddata is outputted while the processed data is reproduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing a music server according toone embodiment of the present invention and a system employing the musicserver;

FIG. 2 is a block diagram showing one example of construction of themusic server;

FIG. 3 schematically shows a signal flow in the process during whichaudio data is read by a CD-ROM drive and written in a hard disk drive;

FIG. 4 schematically shows a signal flow in the process during whichcompressed audio data is read out of the hard disk drive and introducedto a terminal after being subjected to the reproducing process;

FIG. 5 is a block diagram showing one example of construction of aportable recording and playback unit;

FIG. 6 is a block diagram showing another example of the portablerecording and playback unit;

FIG. 7 is a flowchart showing one example of processing executed in themusic server when audio data on a CD is written in the hard disk drive;

FIG. 8 is formed of flowcharts A and B showing one example of thebilling process executed when the CD audio data is written in the harddisk drive at a high data rate;

FIG. 9 is a flowchart showing one example of processing to move theaudio data according to the present invention;

FIG. 10 is a block diagram showing a part of the entire construction ofthe music server which is required for performing high-rate writing fromthe CD into the hard disk drive (HDD) and playback of the CD;

FIG. 11 is a flowchart showing a data flow in the high-rate writingprocess;

FIG. 12 is a flowchart showing a data flow in the processing forequi-rate playback of the CD;

FIGS. 13A and 13B are flowcharts showing the reproducing processexecuted when the audio data is written in the HDD while beingreproduced from the CD;

FIGS. 14A and 14B are flowcharts showing the writing process executedwhen the audio data is written in the HDD while being reproduced fromthe CD;

FIG. 15 is a sequence chart showing one example of how data flows invarious components in more detail;

FIG. 16 is a diagram showing one example of data amounts read out of theCD in the reproducing and writing processes;

FIG. 17 is a diagram showing, on a time base, one example of reading ofPCM data from the CD;

FIG. 18 is a block diagram showing one example of construction adaptablefor a first modification;

FIG. 19 is a flowchart for explaining one example of a data flow in thereproducing process executed during high-rate writing into the HDDaccording to the first modification;

FIG. 20 is a sequence chart showing one example of data flows in variouscomponents in more detail according to the first modification;

FIG. 21 is a block diagram showing one example of construction adaptablefor a second modification;

FIG. 22 is a flowchart showing one example of a data flow in the writingprocess according to the second modification;

FIG. 23 is a flowchart showing one example of a data flow when MP3 dataread out of a CD-ROM is directly written in the HDD without beingsubjected to decoding and compression-coding in accordance with theATRAC method;

FIG. 24 is a flowchart showing a data flow in the reproducing process ofthe MP3 data recorded on the CD-ROM;

FIG. 25 is a sequence chart showing one example of how data flows invarious components in more detail according to the second modification;

FIG. 26 is a functional block diagram of the music server of theembodiment, showing primarily a signal flow;

FIG. 27 is a functional block diagram of a music server according to thefirst modification of the embodiment, showing primarily a signal flow byway of example;

FIG. 28 is a functional block diagram of the music server according tothe second modification of the embodiment, showing primarily a signalflow by way of example;

FIG. 29 is a functional block diagram of a music server according to athird modification of the embodiment, showing primarily a signal flow byway of example;

FIG. 30 is a functional block diagram of a music server according to afourth modification of the embodiment, showing primarily a signal flowby way of example;

FIG. 31 is a functional block diagram of a music server according to afifth modification of the embodiment, showing primarily a signal flow byway of example;

FIG. 32 is a diagram showing the basic concept of a real time operatingsystem (OS) applicable for the present invention;

FIG. 33 is a diagram showing one example of task control for a pluralityof tasks executed by the real time OS;

FIG. 34 is a diagram schematically showing one example of therelationship among the tasks when the real time OS is applied to themusic server of the embodiment;

FIG. 35 is a functional block diagram representing the case where thetasks are allocated to respective components of the music server of theembodiment;

FIG. 36 is a diagram schematically showing process flows among the tasksexecuted in the embodiment;

FIGS. 37A and 37B are flowcharts showing one example of processingexecuted by a task CdReadTask and a task CoderWriteTask;

FIGS. 38A and 38B are flowcharts showing one example of processingexecuted by a task HdWriteTask and a task CoderReadTask;

FIGS. 39A and 39B are flowcharts showing one example of processingexecuted by a task CdPlayTask and a task PcmWriteTask;

FIG. 40 is a chart showing, in more detail, one example of data flows invarious components during the high-rate writing process for a CD in theembodiment, including bank switching in DRAMs;

FIG. 41 is a chart showing, in more detail, one example of data flows invarious components during the equi-rate playback of the CD in theembodiment, including bank switching in a DRAM;

FIG. 42 is a functional block diagram representing the case where thetasks are allocated to respective components of the music serveraccording to the first modification of the embodiment;

FIG. 43 is a functional block diagram representing the case where thetasks are allocated to respective components of the music serveraccording to the second modification of the embodiment;

FIG. 44 includes flowcharts A, B, and C showing one example ofprocessing executed by a task CoderReadTask2 on the input side of theDRAM, and a task CoderWriteTask2 and the task PcmWriteTask both on theoutput side of the DRAM,; and

FIG. 45 is a functional block diagram representing the case where thetasks are allocated to respective components of the music serveraccording to the fifth modification of the embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of the present invention will be described below withreference to the drawings. FIG. 1 schematically shows a music server towhich the present invention is applied, and a system employing the musicserver. A music server 50 comprises a main server unit 51 and a pair ofleft and right speaker units 52L, 52R. The main server unit 51 includesa display unit 53 comprising an LCD (Liquid Crystal Display) panel, anda CD loader 54 through which a CD is inserted into the main server unit51.

Though not shown in FIG. 1, the main server unit 51 also includes aconsole comprising a plurality of control switches with which the usercan control the function of the main server unit 51. A signal receivingportion for receiving an infrared signal, for example, may be providedon the main server unit 51 to remotely control the function of the mainserver unit 51 by a remote commander. Further, the main server unit 51includes a controller as described below, and various operations of themain server unit 51 are controlled by the controller in accordance withpredetermined programs stored in, for example, a ROM beforehand.

When the user loads a CD 55 in the main server unit 51 through the CDloader 54 and performs a predetermined operation on the console (notshown), playback of the CD 55 is started. A playback signal reproducedfrom the CD 55 is outputted through speaker units 52L, 52R so that theuser may enjoy music recorded on the CD 55. When the CD 55 includes textdata, such as the titles of musical compositions, the titles and so onare displayed on the display unit 53 in accordance with the text data.

The music server 50 includes a large-capacity storage system in the formof a hard disk drive, for example. The storage medium in the form of ahard disk can write therein playback data reproduced from the CD 55which has been loaded in the main server unit 51 through the CD loader54, when the user performs a predetermined operation on the console (notshown). On that occasion, it is possible to select one of an ordinarywriting method of writing the data at the same transfer rate as thestandard playback rate of the CD 55 and a high-rate writing method ofwriting the data at a transfer rate higher than the standard playbackrate of the CD 55. In the writing at a high transfer rate, aftercompletion of a billing process according to a predetermined procedure,the user is allowed to select a CD or select a piece of music recordedon a CD and to write played-back data, that is, audio data reproducedfrom the CD, at a transfer rate higher than the standard playback rateof the CD.

In the music server 50, the audio data reproduced from the CD 55 iscoded and compressed by a predetermined method such as ATRAC and thenwritten as compressed audio data. In this way, about 1000 pieces ofmusic can be written or stored in a hard disk having a typical capacityof 6 GByte. A list of the titles of musical compositions written orstored in the hard disk is displayed on the display unit 53. Inaccordance with the music titles displayed on the display unit 53, theuser can select and play back any desired one of the musicalcompositions written or stored in the hard disk. Because a hard disk isadapted for random access, the music server 50 can read a large amountof audio data written or stored in the hard disk in any desired sequenceand reproduce the audio data in a continuous manner.

While various methods are available for compression-coding, thisembodiment employs a method called ATRAC2 (Adaptive Transform AcousticCoding 2) and disclosed in U.S. Pat. No. 5,717,821. This is acompression-coding method used in the portable audio data playerdescribed above and is an advanced version of ATRAC. More specifically,according to ATRAC2, compression-coding of audio data is performed in acombination of transform coding and entropy coding by utilizing themasking effect and the frequency dependency of a minimum audible limitbased on the auditory properties. Audio data can be encoded and decodedat a high bit rate with a relatively small scale of hardware whilemaintaining high sound quality. Other methods, such as ATRAC3, MPEG2 AAC(Advance Audio Codec), MP3 (MPEG1 Audio Layer 3), TwinVQ(Transform-Domain Weighted Interleave Vector Quantization), or MS Audio(WMA: Windows Media Audio) may be used instead. Note that thecompression-coding method is not limited to ATRAC2, and ATRAC3, which isa further advanced version of ATRAC2, is also usable.

The music server 50 can be connected to an external system, such as anInternet server 60 via a communication line 61, such as a publictelephone line. By connecting the music server 50 to the Internet server60 via the communication line 61, the user can obtain variousinformation from the Internet. The Internet server 60 includes adatabase, such as title information of commercially available music CDs.A specific key is allocated for the user to utilize the database. Byoperating the specific key at the time of utilizing the database, theuser can obtain data attendant on individual Cds, such as titleinformation of the CDs.

The Internet server 60 also executes the billing process for the musicserver 50 depending on the service supplied to the user. When the userperforms the above-described high-rate writing for the CD 55, dataindicating that the music server 50 is going to carry out the high-ratewriting is communicated to the Internet server 60. The billing processis thereby executed for the user who is going to perform the high-raterecording. Then, the user is allowed to select a CD or a piece of musicand to perform the high-rate recording.

The billing process has been described above as being executed by theInternet server 60 that includes various additional informationattendant on CDs, but the present invention is not limited to such anexample. As an alternative, the billing process may be executed byanother server connected to the Internet. As a further alternative, thebilling process may be executed via a dedicated network separate fromthe Internet.

A portable recording and playback unit 70 includes a storage mediumcomprising a hard disk or a flash memory, such as a semiconductormemory, a magnetic memory or an optical memory. Any other suitablestorage or recording medium is also usable so long as it can follow theplayback data rate of music. By connecting the portable recording andplayback unit 70 to the music server 50 through a connecting line 71,the audio data recorded in the music server 50 can be transferred to theportable recording and playback unit 70 for writing of the audio data inthe storage medium of the unit 70. At this time, on the side of themusic server 50, the audio data that has been transferred to theportable recording and playback unit 70 is brought into such a statethat the transferred audio data still remains in the storage medium,such as a hard disk or a flash memory, but cannot be reproduced. Thestorage or recording medium used in the portable recording and playbackunit 70 has a capacity on the order of 200 MByte and can store or recordaudio data for several tens of music pieces. Note that, in the followingdescription, a storage device or medium comprising a semiconductormemory, such as a flash memory, and a recording medium in the form of adisk, such as a hard disk will be referred to together as a storagemedium.

The above-mentioned transfer method used in the present invention, thatis, transfer of the type that when audio data is transferred, the audiodata is stored in a storage medium at the transfer destination while thetransferred audio data still remains on a storage medium at the transfersource but cannot be reproduced, is referred to as “movement”. Byutilizing this “movement”, unlimited copying of the audio data can beprohibited.

Although the music server 50 and the portable recording and playbackunit 70 are connected to each other through the connecting line 71 inthe above-described example, the present invention is not limited tosuch an arrangement. For example, mutually fitting portions may beprovided on the music server 50 and the portable recording and playbackunit 70. Thus, the portable recording and playback unit 70 may bejointly fitted to the music server 50 so that data is directlytransferred between the server 50 and the unit 70. Instead of electricalconnection, audio data may be transferred between the music server 50and the portable recording and playback unit 70 with an infrared signal,for example, by providing, in both the server 50 and the unit 70,interfaces for transferring data with an infrared signal in conformitywith the IrDA (Infrared Data Association) standards.

Further, the music server 50 can transfer information between itself andvarious media by providing predetermined interfaces in the music server50. For example, by providing an interface adapted for a PC card 80 inthe music server 50, audio data supplied via the PC card 80 can be takeninto the music server 50, and data can be transferred between a personalcomputer and the music server 50. Also, by providing a serial digitalinterface using an optical cable in the music server 50, audio data canbe transferred between the music server 50 and another digital audiodata recording and playback unit, such as a disk recorder 81, using asmall-sized magneto-optical disk with a diameter of 64 mm. In thisexample, a disk cartridge 82 containing a small-sized magneto-opticaldisk therein is loaded in the disk recorder 81, and audio datareproduced from the magneto-optical disk in the disk cartridge 82 issupplied to the music server 50. Likewise, by providing an IEEE 1394interface or the like in the music server 50, a set-top box 83 for CATV(Cable Television) and satellite broadcasting can be connected to theserver 50. IEEE 1394 is the interface standard stipulated by theInstitute of Electrical and Electronics Engineers.

A PC card 80, which is a card type peripheral device for personalcomputers in conformity with the standards jointly stipulated by thePCMCIA (Personal Computer Memory Card International Association) in USAand JEIDA (Japan Electronic Industry Development Association) in Japancan also be inserted in the main server unit 51.

The music server 50 may include, as an incorporated application, a WWW(World Wide Web) browser. By connecting the music server 50 to theInternet server 60 via the communication line 61, the music server 50can search various contents described in HTML (Hypertext MarkupLanguage) and residing on the Internet, and can display the desiredinformation on the display unit 53.

With the construction described above, the user can not only reproducethe audio data stored or written in the music server 50 for listening tothe audio data through the speaker units 52L, 52R, but the user can alsoload the CD 55 in the server 50 through the CD loader 54 for playback ofthe CD 55.

Through communication between the music server 50 and the Internetserver 60, the music server 50 can automatically obtain the titleinformation of the CD 55, which is loaded in the music server 50 throughthe CD loader 54, from the Internet server 60 via the communication line61. The information obtained from the Internet server 60 is stored inthe music server 50, and the stored title information are displayed onthe display unit 53 of the music server 50 as needed.

More specifically, the information specific to the user, hereinafterreferred to as user information, such as the user ID data of the musicserver 50, is sent from the music server 50 to the Internet server 60.On the side of the Internet server 60, the checking process and thebilling process are executed in accordance with the received userinformation. Also, the media information of a CD requested by the useror a CD under playback is sent from the music server 50 to the Internetserver 60. In accordance with the received media information, theInternet server 60 searches for additional information attendant on theaudio data, such as the song title, the names of the artist, composerand songwriter, words, and a jacket image. Then, the Internet server 60transmits the information regarding the CD requested by the user back tothe music server 50.

For example, the TOC (Table Of Contents) information of the CD 55 issent as the media information to the Internet server 60. A databasecapable of searching for additional information corresponding to theaudio data based on the TOC information is constructed in the Internetserver 60. The Internet server 60 may also obtain the additionalinformation by searching another WWW server on the Internet. TheInternet server 60 searches for the additional information correspondingto the audio data by using the received TOC information as the mediainformation. For example, the search can be made based on timeinformation of each musical composition recorded on the CD 55, the timeinformation being included in the TOC information.

The additional information obtained by the search is sent from theInternet server 60 to the music server 50. In the music server 50, thereceived additional information is displayed on the display unit 53 andwritten in a hard disk drive together with the TOC information of the CD55 by a CPU, described later in connection with FIG. 2. The additionalinformation obtained by the search can be displayed on the music server50 with the incorporated WWW browser software, by sending the additionalinformation from the Internet server 60 to the music server 50 in theform of an HTML file.

If another URL (Uniform Resource Locator) is described in the additionalinformation, the user can access, from the music server 50, the homepage on the Internet indicated by the other URL.

Further, by communicating data between the music server 50 and theInternet server 60, the music server 50 can write the audio data of theCD 55, which is loaded in the music server 50 through the CD loader 54,in the storage medium of the music server 50 in about two minutes foreach CD, for example, at a higher data rate than the standard playbackdata rate prescribed for the CD 55. When no communication is madebetween the music server 50 and the Internet server 60, the music server50 stores the audio data of the CD 55 in the storage medium of the musicserver 50 at the same data rate as the standard playback data rateprescribed for the CD 55.

By connecting the music server 50 to the portable recording and playbackunit 70 through the connecting line 71, the audio data stored or writtenin the music server 50 can be transferred and moved to the portablerecording and playback unit 70. The moved audio data can be reproducedby the portable recording and playback unit 70 even when the server 50and the unit 70 are not connected through the connecting line 71,allowing the user to listen to the reproduced audio data with aheadphone 72, for example. On the side of the music server 50, thetransferred and moved audio data is brought into a state where it cannotbe reproduced.

FIG. 2 shows one example of construction of the music server 50.Similarly to the construction of an ordinary personal computer, themusic server 50 comprises a RAM 5, a ROM 6, a flash memory 7, and a CPU8 which are interconnected via a bus 40. The CPU 8 functions as acontroller and controls the overall operation of the music server 50.

Programs for controlling the operation of the music server 50 are storedin the ROM 6 beforehand. In the music server 50, the stored programsenable the CPU 8 to execute the operation corresponding to the user'smanipulation made on an input console 1. A data area and a task area,which are required for execution of the programs, are temporarilysecured in the RAM 5 and the flash memory 7. A program loader is storedin the ROM 6 so that a program itself may be loaded in the flash memory7 with the program loader stored in the ROM 6.

The input console 1 comprises a plurality of push- and rotary-typecontrol keys and a plurality of switches operated respectively by thecontrol keys. The input console 1 is not limited to such an example, butmay comprise a rotatable push-type control member called a jog dial, atouch panel formed on an LCD, or the like. As a matter of course, theinput console 1 may comprise a switch mechanism responsive to pressingby the user. A signal corresponding to the user's manipulation made onthe input console 1 is supplied to the CPU 8 via the bus 40. Inaccordance with the signal from the input console 1, a control signalfor controlling the operation of the music server 50 is produced by theCPU 8. The music server 50 is operated in accordance with the controlsignal produced by the CPU 8.

An infrared interface (IrDA I/F) driver 3 and/or a USB (Universal SerialBus) driver 4 are connected to the bus 40. A keyboard 2 is designed tobe connectable to the drivers 3, 4 by radio communication or electricalconnection. Using the keyboard 2, the user can easily enter, forexample, the music title, the name of the artist, etc. corresponding tothe audio data to be written. Also, data may be transferred through theinfrared interface driver 3 or the USB driver 4, which can be consideredoptional.

A CD-ROM drive 9 is connected to the bus 40, and the CD 55 is loaded inthe CD-ROM drive 9 through the CD loader 54 as described above. In theCD-ROM drive 9, the audio data is read out of the CD 55 at the standardplayback data rate prescribed for the CD 55. The CD-ROM drive 9 can alsoread the audio data of the CD 55 at a higher date rate, such as 16 or 32times as fast as the prescribed standard playback data rate.

The CD-ROM drive 9 is not limited to the above-mentioned example, butmay be adaptable for any other suitable disk-shaped recording medium inwhich audio data is stored, for example, a magneto-optical disk or a DVD(Digital Versatile Disk). Alternatively, a drive adaptable for a memorycard is also usable. Further, data read by the CD-ROM drive 9 is notlimited to audio data, and image data, text data, program data, can alsobe read by the CD-ROM drive 9.

A hard disk drive (hereinafter abbreviated to HDD) 10 is connected tothe bus 40. Audio data read by the CD-ROM drive 9 is written in the HDD10. As a pre-process for writing the audio data in the HDD 10, the audiodata read by the CD-ROM drive 9 is supplied to a compression encoder 12via the bus 40 and an audio DRAM 11.

The compression encoder 12 executes the compression-coding process ofthe audio data by the compressing method disclosed in the above-citedU.S. Pat. No. 5,717,821, for example. A compression bit rate of theaudio data by the compression encoder 12 is selected from two low andhigh bit rates under control of the CPU 8. The low compression bit ratecorresponds to the standard playback data rate prescribed for the CD 55in connection with the CD-ROM drive 9. The compression bit rate isswitched over depending on the playback data rate of the CD 55 in theCD-ROM drive 9. For example, an encoding algorithm depending on thecompression bit rate is operated in the compression encoder 12.

The manner of changing the compression bit rate in the compressionencoder 12 is not limited to the above-described example. As analternative, the compression bit rate may be changed by switching overthe clock frequency of the compression encoder 12, or by preparingseparate units of hardware. Further, the compression encoder 12 capableof high-rate compression may be operated at a low compression bit ratethrough thinning of the processing. The compressed audio data resultingfrom the compression-coding executed by the compression encoder 12 iswritten and stored in the HDD 10 through the DRAM 11.

Although the compressed audio data resulting from the compression-codingexecuted by the compression encoder 12 is written in the HDD 10 in thisembodiment, the audio data read by the CD-ROM drive 9 may be directlysupplied to the HDD 10 to be written and stored in a hard disk of theHDD 10.

In this embodiment, a sound signal inputted from a microphone, which isconnected to a terminal 13, through an amplifier 14 and a sound signalinputted from a line input terminal 15 are supplied to the compressionencoder 12 through an A/D converter 16. Those sound signals can be thuswritten in the HDD 10 after being subjected to compression-coding by thecompression encoder 12. Further, a digital optical signal is supplied tothe compression encoder 12 from a digital optical input terminal 17through an IEC 958 (International Electrotechnical Commission 958)encoder 18. A sound signal supplied as a digital optical signal can bethus written on the disk of the HDD 10 after the compression-coding bythe compression encoder 12.

The compression encoder 12 has been described as using the encodingalgorithm disclosed in the above-cited U.S. Pat. No. 5,717,821, but thepresent invention is not limited to that example. The compressionencoder 12 may use any other suitable encoding algorithm so long as itcan compress information. In addition to the above-described algorithms,other encoding algorithms such as PASC (precision adaptive sub-bandcoding), RealAudio (trade name), and LiquidAudio (trade name) are alsousable in the compression encoder 12.

A modem 20 is connected to the bus 40. An external network 19, such as apublic telephone line, CATV, a satellite line or wireless communication,is connected to the modem 20. The music server 50 can communicate withthe external network 19 through the modem 20.

The music server 50 is connected to the Internet via the externalnetwork 19 for communication with the Internet server 60 in a remotelocation. Various information including a request signal, the mediainformation regarding the CD 55 loaded in the CD-ROM drive 9, the userID data assigned to the music server 50 in one-to-one relationbeforehand and other user information, as well as billing informationfor the user, are transmitted from the music server 50 to the Internetserver 60.

When the various information such as the media information and the userinformation are transmitted to the Internet server 60, the Internetserver 60 executes the checking process and the billing process inaccordance with the received user information, such as the user ID data,and searches for the additional information corresponding to the audiodata based on the received media information, the located additionalinformation being sent back to the music server 50.

Although the additional information corresponding to the audio data issent back to the music server 50 in the above example, the audio datamay be directly supplied via the external network 19 in response to auser's request. In other words, the user can download audio data fromthe Internet server 60 by using the music server 50. Thus, audio datacan be sent back in accordance with the media information. This featureenables the user to obtain a bonus track of a predetermined CD throughcommunication.

The compressed audio data, which has been written and stored in the HDD10 after being coded and compressed by the compression encoder 12, isread out of the HDD 10 for reproduction and the read-out data issupplied to a compression decoder 21 via the bus 40. The compressedaudio data read out of the HDD 10 is decoded and decompressed in thecompression decoder 21, and the decoded audio data is fed out at aterminal 24 through a D/A converter 22 and an amplifier 23. The audiodata is then supplied from the terminal 24 to the speaker units 52L, 52Rof FIG. 1 for playback of music. Though not shown in FIG. 2, there areactually provided two signal lines from the D/A converter 22 to theterminal 24 through the amplifier 23 corresponding to stereo outputs.Likewise, two terminals 24 are also provided corresponding to stereooutputs.

The compression decoder 21 uses a decoding algorithm corresponding tothe encoding algorithm used in the compression encoder 12. Thecompression decoder 21 and the compression encoder 12 may implementtheir functions through software processing executed by the CPU 8without resorting to hardware.

A liquid crystal display (LCD) device 26, which constitutes the displayunit 53, is connected to the bus 40 through an LCD driver 25. A drawingcontrol signal is supplied from the CPU 8 to the LCD driver 25 via thebus 40. The LCD 26 is operated by the LCD driver 25 in accordance withthe supplied drawing control signal, and the desired display is made onthe display unit 53.

For example, an operating menu of the music server 50 is displayed onthe LCD 26. As another example, a title list of the compressed audiodata, which has been written and stored in the HDD 10, is displayed onthe LCD 26. Display of the title list on the LCD 26 is performed basedon data stored in the HDD 10 because the additional informationtransmitted from the Internet server 60 is supplied to the HDD 10 afterbeing decoded. As still another example, a folder or a jacket imagecorresponding to the compressed audio data, which has been selected forreproduction, may be displayed on the LCD 26 in accordance with theadditional information transmitted from the Internet server 60.

When the user operates a remote control device, not shown, in the inputconsole 1 or the keyboard 2 based on the display on the LCD 26, the CPU8 starts reproducing control of the audio data instructed by the user.Further, based on the display on the LCD 26, the user can instruct theCPU 8 to control not only erasure of the selected audio data, but alsocopying and movement of the selected audio data to an external device.For example, where the input console 1 is in the form of a touch panelprovided on the LCD 26, the user can operate the music server 50 bytouching the touch panel following the display on the LCD 26. Thus, theuser can manage and control the audio data written and stored in the HDD10 by utilizing the LCD 26 as an interface.

This embodiment is adapted for IEEE 1394 and a PC card to interfacebetween the music server 50 and external general information equipment.To that end, an IEEE 1394 interface 28 is connected to the bus 40through an IEEE 1394 driver 29. Likewise, a PC card slot 31 is connectedto the bus 40 through a PC card driver 30.

Data can be transferred between the music server 50 and a personalcomputer through the IEEE 1394 interface 28. Also, the IEEE 1394interface 28 enables audio data to be taken in from an IRD (IntegratedReceiver/Decoder) for satellite broadcasting, a small-sizedmagneto-optical disk or an optical disk with a diameter of about 64 mm,a DVD (Digital Versatile Disk: trade name), and a digital video tape. Byloading a PC card into the PC card slot 31, it is possible to easilyachieve system expansion including various peripheral equipment, such asan external storage or any other media drive, a modem, a terminaladapter, and a capture board.

An interface 34 serves as an interface through which audio data istransferred between the music server 50 and another correspondingrecording and playback apparatus. The another recording and playbackapparatus comprises the above-mentioned portable recording and playbackunit 70 shown in FIG. 1. Alternatively, the other recording and playbackapparatus may comprise another music server.

The interface 34 is connected to the bus 40 through an interface driver33. The other recording and playback apparatus includes an interface 35matched with the interface 34. By electrically connecting both theinterfaces 34 and 35 through the predetermined connecting line 71, theaudio data written and stored in the HDD 10 can be transferred from themusic server 50 to the other recording and playback apparatus.

FIG. 3 schematically shows a signal flow in the process during whichaudio data is read by the CD-ROM drive 9 and written in the HDD 10. Theaudio data read by the CD-ROM drive 9 is first stored in the DRAM 11serving as a buffer memory via the bus 40. The audio data is read out ofthe DRAM 11 at predetermined timing and supplied to the compressionencoder 12 via the bus 40. The compression encoder 12 is set, asdescribed above, to the predetermined compression bit rate correspondingto the playback data rate of the CD-ROM drive 9. The audio data is codedand compressed by the compression encoder 12 and then stored again inthe DRAM 11 serving as a buffer memory. The compressed audio data isread out of the DRAM 11 at predetermined timing and supplied to the HDD10 via the bus 40 for writing on the disk of the HDD 10. On thisoccasion, as described above, the information of the CD 55 underplayback by the CD-ROM drive 9 is transmitted to the Internet server 60,and the additional information attendant on the CD 55 transmitted fromthe Internet server 60 is also written on the disk of the HDD 10. Then,the additional information is managed by the CPU 8 as one group of data,together with the compressed audio data obtained from the audio datathat has been read out of the CD 55.

FIG. 4 schematically shows a signal flow in the process during which thecompressed audio data is read out of the HDD 10 and introduced to theterminal 24 after being subjected to the reproducing process. Thecompressed audio data read out of the HDD 10 is once stored in the DRAM11 serving as a buffer memory via the bus 40. The compressed audio datais read out of the DRAM 11 at a predetermined timing and supplied to thecompression decoder 21 via the bus 40. The compressed audio data isdecoded and decompressed by the compression decoder 21, and resultingaudio data is supplied to the D/A converter 22. The audio data isconverted into an analog sound signal by the D/A converter 22 and isintroduced, as a playback output, to the terminal 24 after beingamplified by the amplifier 23. If a speaker is connected to the terminal24, the user can enjoy the played-back music through the speaker. Onthis occasion, the additional information read out from the disk of theHDD 10 along with the compressed audio data is decoded by the CPU 8 andthe music title and the like are displayed on the display unit 53.

FIG. 5 shows one example of construction of the portable recording andplayback unit 70 that is employed as the above-mentioned other recordingand playback apparatus. The portable recording and playback unit 70 hasbasically the same construction as that of the music server 50 shown inFIG. 2. Usually, the interface 34 on the side of the music server 50 isdisconnected from the interface 35 on the side of the portable recordingand playback unit 70, and the unit 70 is carried as a single unit withthe user.

Similarly to the construction of an ordinary personal computer, theportable recording and playback unit 70 comprises a RAM 103, a ROM 104,and a CPU 105, which are interconnected via a bus 130. Of course, aflash memory may also be provided as with the above-describedconstruction of the music server 50. The CPU 105 functions as acontroller and controls the overall operation of the portable recordingand playback unit 70.

Programs for controlling the operation of the portable recording andplayback unit 70 are stored in the ROM 104 beforehand. In the portablerecording and playback unit 70, the stored programs enable the CPU 105to execute the operation corresponding to the user's manipulation madeon an input console 102. A data area and a task area, which are requiredfor execution of the programs, are temporarily secured in the RAM 103.

The input console 102 comprises, for example, a plurality of push- androtary-type control keys and a plurality of switches operatedrespectively by the control keys. The input console 102 is not limitedto such an example, but may comprise a rotatable push-type controlmember called a jog dial, a touch panel formed on an LCD, or the like.As a matter of course, the input console 102 may comprise a mechanicalswitch mechanism responsive to pressing by the user. A signalcorresponding to the user's manipulation made on the input console 102is supplied to the CPU 105 via the bus 130. In accordance with thesignal outputted from the input console 102 corresponding to the user'smanipulation of the control key made on the input console 102, the CPU105 produces a control signal for controlling the operation of theportable recording and playback unit 70. The operation of the portablerecording and playback unit 70 is switched over and controlled inaccordance with the control signal produced by the CPU 105.

The audio data, which is read out of the HDD 10 and instructed to betransferred from the music server 50 to the portable recording andplayback unit 70, is transferred or supplied to the unit 70 through theinterface 34, the interface 35, and the connecting line between both theinterfaces 34, 35. At the same time, the additional informationcorresponding to the audio data, which has been instructed to betransferred, is also transmitted to the portable recording and playbackunit 70 along with the transferred audio data. Where mutually fittingportions are provided on the music server 50 and the portable recordingand playback unit 70, both the interfaces 34, 35 are directly connectedto each other so that the audio data is transferred between the server50 and the unit 70. Alternatively, where IrDA interfaces are provided onboth the server 50 and the unit 70, the audio data is transferredbetween the server 50 and the unit 70 using an infrared signal.

The audio data transferred from the music server 50 to the portablerecording and playback unit 70 is supplied to an HDD 106, which is anaudio data storing medium built in the unit 70, via an interface driver101 and the bus 130 for writing on a platter of the HDD 106.

The audio data storing medium in the portable recording and playbackunit 70 is not limited to the HDD 106, but may comprise a flash memory,for example. Further, any other suitable storing or recording medium,such as a magneto-optical disk, can also be used as the audio datastoring medium so long as it is able to follow the playback data rate ofthe audio data. When the audio data storing medium in the portablerecording and playback unit 70 has a storage capacity on the order of200 MByte, it can store several tens of music pieces. The platter of theHDD 106 in the unit 70 records thereon the audio data transmitted fromthe music server 50 along with the additional information correspondingto the transmitted audio data.

In this embodiment, the audio data transferred and written in the HDD106 is compressed audio data that has been already subjected to thecompression-coding in the music server 50. The present invention is notlimited to this embodiment, and the portable recording and playback unit70 may be supplied with audio data, which has not been coded andcompressed, for writing on the platter of the HDD 106. In such a case,the audio data played back and read out of the CD 55 loaded in theCD-ROM drive 9 of the music server 50 is directly supplied to theportable recording and playback unit 70 through the interface driver101. It is, however, needless to say that when the audio data isdirectly supplied to the unit 70 the amount of audio data that can bestored in the unit 70 is noticeably restricted.

As a pre-process for writing the audio data on the platter of the HDD106, the supplied audio data is temporarily stored in an audio DRAM 107connected to the bus 130. The audio data read out of the DRAM 107 issupplied to a compression encoder 108 via the bus 130. The compressionencoder 108 executes the compression-coding process of the audio data bythe same encoding algorithm as used in the compression encoder 12 of themusic server 50. The audio data coded and compressed by the compressionencoder 108 is supplied to the DRAM 107 and temporarily stored in theDRAM 107 again. Finally, the compressed audio data stored in the DRAM107 is read and written on the platter of the HDD 106.

As described above, when the compressed audio data stored in the HDD 10is instructed to move, that is, to be transmitted and transferred fromthe music server 50 to the portable recording and playback unit 70, thecompressed audio data in the HDD 10 is brought into such a state thatthe transferred audio data still remains in the HDD 10 but cannot beread out of the HDD 10 for reproduction. The compressed audio datahaving been moved to the unit 70 can be reproduced at the movementsource, that is, in the music server 50, only when the moved audio datais returned back to the storage medium at the movement source, that is,to the HDD 10 in the music server 50. At this time, the compressed audiodata returned to the music server 50 is deleted from the storage mediumat the movement destination, that is, the platter of the HDD 106 in theunit 70.

In this embodiment, a sound signal inputted from a microphone, which isconnected to a terminal 109, through an amplifier 110 and a sound signalinputted from a line input terminal 111 are supplied to the compressionencoder 108 through an A/D converter 112. Those sound signals suppliedthrough the A/D converter 112 can be written in the HDD 106 after beingcoded and compressed by the compression encoder 108. Further, a digitaloptical signal is supplied to the compression encoder 108 from a digitaloptical input terminal 113 through an IEC 958 encoder 114. A soundsignal supplied as a digital optical signal can be thus written on theplatter of the HDD 106 after being coded and compressed by thecompression encoder 108. If the portable recording and playback unit 70is a play-only unit that is able to only reproduce the compressed audiodata, the above-mentioned A/D converter 112 and encoder 108 can be alldispensed with.

The compressed audio data is read out of the HDD 106 for reproductionand is supplied to the compression decoder 115 via the bus 130. Thesupplied compressed audio data is subjected to the decompressing processin the compression decoder 115, and resulting decoded and decompressedaudio data is fed out at a terminal 118 through a D/A converter 116 andan amplifier 117. For example, the headphone 72 is connected to theterminal 118. The user can listen to the played-back music by putting onthe headphone 72. Though not shown in FIG. 5, there are actuallyprovided two signal lines from the D/A converter 116 to the terminal 118through the amplifier 117 corresponding to stereo outputs for L- andR-channels. Likewise, two terminals 118 are also provided correspondingto stereo outputs for L- and R-channels.

An LCD 120 is connected to the bus 130 through an LCD driver 119. Adrawing control signal is supplied from the CPU 105 to the LCD driver119 via the bus 130. The LCD 120 is operated in accordance with thesupplied drawing control signal, and certain display is made on the LCD120. An operating menu of the portable recording and playback unit 70, atitle list of the audio data stored in the HDD 106, and the like aredisplayed on the LCD 120. As another example, a folder or a jacket imagecorresponding to the audio data, which has been selected from the audiodata stored in the HDD 106 for reproduction, may be displayed on the LCD120 in accordance with the additional information stored in the HDD 106.

When the user operates a pointing device in the input console 102 basedon the display on the LCD 120, one set of the compressed audio datastored in the HDD 106 is selected and reproduced. Further, based on thedisplay on the LCD 120, the user can instruct the CPU 105 to controlerasure, copying and movement of the selected compressed audio data. Forexample, the user can input an instruction for operating the portablerecording and playback unit 70 by touching a touch panel provided on theinput console 102 following the display on the LCD 120. Thus, the usercan control management, writing and reproduction of the compressed audiodata stored in the HDD 106 by utilizing the LCD 120 as an interface.

Though not shown in FIG. 5, the portable recording and playback unit 70is driven by a battery. Therefore, the unit 70 includes a power supplyunit and a charging unit, the power supply unit comprising, as a powersupply source, a general secondary battery or dry cell. Where the musicserver 50 and the portable recording and playback unit 70 are directlyconnected to each other through a connecting line or mutually fittingportions, electric power is supplied to the charging unit together withtransfer of the audio data for charging the secondary battery in theunit 70. As a matter of course, the secondary battery in the unit 70 maybe charged using an external charging power source. Incidentally, eitherone of a non-charging power source using a dry cell or a charging powersource using a secondary battery may be provided as the power supplyunit.

FIG. 6 shows another example of the portable recording and playback unit70. Note that components in FIG. 6 in common with those in FIG. 5 aredenoted by the same numerals and a detailed description thereof is notrepeated here. A portable recording and playback unit 170 shown in FIG.6 differs in construction from the unit 70 shown in FIG. 5 in that aswitch circuit 200 is interposed between an HDD or a flash memory 106 aand the bus 130. One contact terminal 200 a of the switch circuit 200 isconnected to the bus 130, and the other contact terminal 200 b isconnected to the interface 35. The HDD 106 a and the bus 130 areseparable by the switch circuit 200.

When the compressed audio data is transferred from the music server 50,the switch circuit 200 is changed over to the side of the contactterminal 200 b for selection of the contact terminal 200 b. The HDD 106a and the bus 130 of the music server 50 are thereby directly connectedto each other through the interfaces 34 and 35. Looking the HDD 106 afrom the CPU 8 of the music server 50 in such a condition, the HDD 106 aappears as a storage medium in the music server 50. Accordingly, the CPU8 of the music server 50 can directly control the HDD 106 a. Thisarrangement enables the compressed audio data to be more easily movedand copied between the music server 50 and the portable recording andplayback unit 170 under control of the CPU.

The operation of the system thus constructed will be described below. Adescription is first made of the function executed by the music server50 alone. FIG. 7 is a flowchart showing one example of processingexecuted when audio data on the CD 55 loaded in the CD-ROM drive 9 iswritten on the disk of the HDD 10 in the music server 50.

In first step SI 0, the CPU waits for a request from the user forwriting the audio data of the CD 55 in the HDD 10. If the user enters awriting request through the input console 1, for example, the processgoes to step S11. In step S11, it is determined whether the writingrequested by the user is “high-rate writing” or “equi-rate writing”. Awriting method, that is, “high-rate writing” or “equi-rate writing”, canbe designated by the user at the same time as when a writing request isentered in above step S10. The term “equi-rate writing” used hereinmeans the operation of reading the audio data at the standard data rateprescribed for the CD 55 and writing the read data on the platter of theHDD 10. The term “high-rate writing” used herein means the operation ofreading the audio data at a data rate two or more times as fast as thestandard data rate prescribed for the CD 55 and writing the read data onthe disk of the HDD 10.

If “high-rate writing” is designated in step S11, the process goes tostep S12. In step S12, a billing system in the server 50 or 60 isstarted up. Processing executed by the billing system in the servers 50or 60 will be described later. After the billing process is executed bythe billing system in the music server 50 and the high-rate writing ispermitted by the Internet server 60 or another device, the process goesto step S13 where the high-rate compressing process is started in thecompression encoder 12. The process then goes to step S15.

On the other hand, if “equi-rate writing” is designated in step S11, theprocess goes to step S14 where the low-rate compressing process isstarted in the compression encoder 12. The process then goes to stepS15.

In step S15, the CD-ROM drive 9 is driven at the predetermined speedunder control of the CPU 8, and the audio data recorded on the CD 55,which is loaded in the CD-ROM drive 9, is read out of the CD 55. Theread audio data is coded and compressed by the compression encoder 12and transferred to the HDD 10 for writing on its disk.

If it is determined in step S16 that the audio data read out of the CD55 has been completely transferred to the HDD 10 after the compression,data transfer from the CD-ROM drive 9 to the HDD 10 is prohibited instep S17. In next step S18, the compression-coding process by thecompression encoder 12 is stopped.

A and B in FIG. 8 are flowcharts showing one example of the billingprocess executed by the billing system in step S12 of the flowchartshown in FIG. 7. The billing process is executed through datacommunication between the music server 50 and the Internet server 60.Flowchart A shows the billing process executed by the billing system inthe music server 50, and flowcahrt B shows the billing process executedby the billing system in the Internet server 60.

After the start of the billing process, in step S20 of A, datacommunication is started between the music server 50 and the Internetserver 60 in accordance with a predetermined protocol. If it isconfirmed in step S21 that connection between both the servers 50 and 60is established to be ready for communication between both the servers 50and 60, the process goes to step S22.

In step S22, the TOC information of the CD 55, which is loaded in theCD-ROM drive 9 and from which the audio data is transferred and writtenin the HDD 10, is sent from the music server 50 to the Internet server60 along with the user ID corresponding to the music server 50. Togetherwith the TOC information of the CD 55, high-rate writing informationindicating selection of the high-rate writing is sent from the musicserver 50 to the Internet server 60.

On the other hand, in B, the Internet server 60 waits until the user ID,the high-rate writing information and the TOC information are suppliedor transmitted from the music server 50 in step S30. If the user ID, thehigh-rate writing information and the TOC information are received bythe Internet server 60, a database in the Internet server 60 or anexternal database is searched in step S31 based on the transmitted TOCinformation. The CD 55 is identified by the search for informationcorresponding to the TOC information.

The billing process is executed in next step S32. An amount of money tobe billed is computed based on information, such as the number ofmusical compositions which have been subjected to the high-rate writing.The billing can be performed by drawing the billed amount on theaccount, which has been opened with a bank and designated by the user,in accordance with the credit card number of the user registered inadvance and corresponding to the user ID. The billing method is notlimited to the above example. For example, the billing can be performedon the side of the music server 50 by a method of providing a functionof reading a prepaid card in the music server 50, sending the presetbilled amount to the music server 50, and subtracting the billed amountfrom the prepaid card inserted by the user. Under control of theInternet server 60, it is also possible to change the billed amountdepending on the contents of the CD 55 and to prohibit writing of theaudio data read out of the CD 55 on the platter of the HDD 10 inaccordance with the TOC information.

In step S33, the billing information is sent to the music server 50.Then, as shown in A of FIG. 8, the substance of the transmitted billinginformation is acknowledged on the side of the music server 50 in stepS23. Also, whether the billing information has been received by themusic server 50 is acknowledged on the side of the Internet server 60 instep S34. When the billing information has been correctly received bythe music server 50 without errors, this fact can be acknowledged bytransmitting acknowledgement data from the music server 50 to theInternet server 60.

Returning to A of FIG. 8, if the billing information received on theside of the music server 50 is acknowledged in step S23, the processgoes to step S24 where the received billing information, etc. aredisplayed on the display unit 53. In step S25, the audio data is readout of the CD 55 at a high bit rate by the CD-ROM drive 9 and subjectedto the compression-coding process at a high compression bit rate in thecompression encoder 12. The compressed audio data from the compressionencoder 12 is supplied to the HDD 10 and written to the disk of the HDD10. Step S25 corresponds to step S15 in FIG. 7.

In this embodiment of the present invention, the music server 50 and theportable recording and playback unit 70 can operate in a cooperativemanner. For example, when audio data is moved from the music server 50to the portable recording and playback unit 70, the cooperation iscarried out between the server 50 and the unit 70. FIG. 9 shows aflowchart of one example of the movement of audio data.

First, it is determined in step S40 whether the music server 50 and theportable recording and playback unit 70 are connected at the interfaces34 and 35. The CPU 8 can detect the connection between the music server50 and the portable recording and playback unit 70 by transferring apredetermined signal between the server 50 and the unit 70. A manner ofdetecting the connection between the music server 50 and the portablerecording and playback unit 70 is not limited to such an example, butmay be performed with a mechanical detecting mechanism. In other words,a mechanical switch mechanism may be provided at a joint portion betweenthe server 50 and the unit 70, so that the CPU 8 can detect theconnection between them.

If the connection between the music server 50 and the portable recordingand playback unit 70 is confirmed in step S40, the CPU 8 determines innext step S41 whether it is requested to move the audio data, which iswritten and stored in the HDD 10, to the portable recording and playbackunit 70. For example, a list of information about the compressed audiodata stored in the HDD 10, including the music titles and so on, isdisplayed on the display unit 53, and the user selects one set of thecompressed audio data from the list displayed on the display unit 53 byusing the pointing device in the input console 1. Further, aninstruction for movement of the selected compressed audio data to theportable recording and playback unit 70 is entered by the user throughthe input console 1.

Various approaches are conceivable to enter an instruction for movementof the selected audio data through the input console 1. For example, abutton for instructing movement of the selected audio data is displayedon the display unit 53, and the user designates the button by using thepointing device in the input console 1. As another example, an icon isdisplayed on the display unit 53 for each set of the compressed audiodata, and the user moves a desired one of the icons onto an iconindicating the portable recording and playback unit 70 as the movementdestination, which is also displayed on the display unit 53, in theso-called drag and drop fashion. As a matter of course, an instructionfor movement of the selected audio data may be entered by operating acontrol switch provided on the input console 1. The CPU 8 detects suchan input operation and determines whether an instruction for movement ofthe selected audio data has been made.

If it is determined in step S41 that the movement of the compressedaudio data is requested, the file size, i.e., the data amount, of thecompressed audio data, for which the movement has been instructed, ischecked in step S42 by the CPU 8 of the music server 50. In next stepS43, an empty storage capacity available for writing, of the HDD 106 ischecked by the CPU 105 of the portable recording and playback unit 70which can transmit and receive data to and from the CPU 8. Then, thefree space of the HDD 106 is compared with the file size of thecompressed audio data, which has been checked in step S43 and for whichthe movement has been instructed, by the CPU 8 of the music server 50.In accordance with a comparison result in step S42, it is determinedwhether the compressed audio data, for which the movement has beeninstructed, can be written in the HDD 106. If the writing in the HDD 106is possible, the process goes to step S45 where transfer of thecompressed audio data, for which the movement from the server 50 to theunit 70 has been instructed, is started.

On the other hand, if the CPU 8 determines in step S43 that theavailable free space of the HDD 106 in the portable recording andplayback unit 70 is insufficient, the process goes to step S44. In stepS44, the compressed audio data already written in the HDD 106 is deletedautomatically or through a predetermined procedure or method by the CPU105 of the unit 70, so that the compressed audio data for which themovement has been instructed may be written in the HDD 106. Thereafter,the process goes to step S45.

Deletion of the compressed audio data in step S44 can be automaticallyperformed under control of the CPU 105 in accordance with apredetermined parameter for the compressed audio data already written inthe HDD 106. One example of conceivable approaches is to count thenumber of times of reproduction for each set of the compressed audiodata written in the HDD 106 of the portable recording and playback unit70 and to delete the compressed audio data in the order of theincreasing number of times of reproduction from the HDD 106, startingfrom the minimum one. As an alternative, the compressed audio datawritten in the HDD 106 may be deleted in accordance with the date atwhich the data was written in the HDD 106, starting from the oldestdate.

When the compressed audio data is automatically deleted in step S44 fromthe HDD 106, there is a possibility that the compressed audio dataimportant for the user may be deleted from the HDD 106. To prevent suchan undesirable occurrence, a warning can be displayed on the displayunit 53 of the music server 50 or the LCD 120 of the portable recordingand playback unit 70 to indicate the fact that the unit 70 is in a stateready for operation to automatically delete the compressed audio datafrom the HDD 106, or represent a list of the data to be deleted. Thecompressed audio data is then deleted from the HDD 106 afterconfirmation by the user. Another conceivable method is to display alist of the compressed audio data already written in the HDD 106 on thedisplay unit 53 of the music server 50 or the LCD 120 of the portablerecording and playback unit 70 and to prompt the user to select thecompressed audio data to be deleted.

When the HDD 106 comes into a state capable of writing one of pluralsets of the compressed audio data written in the HDD 10, for which themovement has been instructed, through the above-described processing insteps S43 and S44, transmission or transfer of the compressed audio datafrom the music server 50 to the portable recording and playback unit 70is started in step S45: Specifically, the compressed audio data read outof the HDD 10 is supplied to the portable recording and playback unit 70via the bus 40 and the interface 34. In the portable recording andplayback unit 70, the compressed audio data supplied via the interface34 is written in the HDD 106 via the interface 35.

The compressed audio data having been transferred to the portablerecording and playback unit 70 still remains in the HDD 10 of the musicserver 50 as it is before the transmission to the unit 70. In thisembodiment, reproduction of the compressed audio data that has beentransferred to the unit 70, that is, playback of the compressed audiodata that has been moved to the unit 70 and still remains in the HDD 10,is prohibited on the side of the music server 50 in step S46. Forexample, at the time when the compressed audio data has been transferredto the unit 70, a playback prohibit flag indicating prohibition ofreproduction is set for the relevant compressed audio data in the HDD10. With the playback prohibit flag thus set, the CPU 8 of the musicserver 50 prohibits reproduction of the compressed audio data that hasbeen transferred to the unit 70. This means that the compressed audiodata stored in the HDD 10 has been virtually moved from the music server50 to the portable recording and playback unit 70. Accordingly, thesystem is managed such that only one of the same plural sets of thecompressed audio data can be reproduced by the server 50 or the unit 70at any time, whereby unauthorized copying of the compressed audio datais prevented.

In next step S47, it is determined whether another set of the compressedaudio data is requested to be moved to the portable recording andplayback unit 70. If the movement of another set of the compressed audiodata is requested, the process returns to step S42. If the movement of afurther set of the compressed audio data is not requested again, aseries of the processes for moving the audio data are ended.

In the above description, one of plural sets of the compressed audiodata stored in the HDD 10 is transferred from the server 50 to the unit70 in steps S42-S46 of the flowchart shown in FIG. 9. The presentinvention is not limited to such an example, however, and plural sets ofthe compressed audio data may be moved together from the server 50 tothe unit 70.

In the embodiment described above, the compressed audio data, which hasbeen moved from the HDD 10 of the music server 50 as the movementsource, is only prohibited from being reproduced, and the compressedaudio data still remains itself in the HDD 10. The present invention isnot limited to the above-described embodiment, however, and thecompressed audio data having been moved may be deleted from the HDD 10,that is to say, the data itself may be erased.

The above embodiment has been described in connection with the case ofmoving the compressed audio data from the music server 50 to theportable recording and playback unit 70. Movement of the compressedaudio data in the opposite direction, that is, movement of thecompressed audio data written in the HDD 106 of the portable recordingand playback unit 70 to the HDD 10 of the music server 50, however, canalso be executed in accordance with similar processing to that shown inthe flowchart of FIG. 9.

In that case, when the compressed audio data, which has been moved fromthe music server 50 to the portable recording and playback unit 70, ismoved back from the unit 70 to the music server 50, the playbackprohibit flag having been set to one of plural sets of the compressedaudio data stored in the HDD 10, which has been moved back from the unit70, is cleared in the music server 50. Clearing of the playback prohibitflag allows the compressed audio data existing in the music server 50 asthe movement source to be reproduced again. On that occasion, thecompressed audio data, which has been stored in the HDD 106 of the unit70 and moved therefrom, is itself erased from the HDD 106. As analternative, the management data for the compressed audio data, whichhas been moved from the HDD 106, is deleted from a management table ofthe HDD 106.

In the present invention, playback of the CD 55 is performed in parallelwith the above-described high-rate writing of the audio data from the CD55 to the HDD 10. FIG. 10 shows a part of the entire construction shownin FIG. 2 which is required for performing the high-rate writing fromthe CD 55 to the HDD 10 and playback of the CD 55. Components in FIG. 10corresponding to those in FIG. 2 are denoted by the same numerals and adetailed description thereof is not repeated here. By referring to FIG.10, the high-rate writing from the CD 55 to the HDD 10 and directplayback of the CD 55 in the ordinary processing will be describedseparately.

FIG. 11 is a flowchart showing a data flow in the high-rate writingprocess. First, the CD 55 is loaded in the CD-ROM drive 9, and the audiodata recorded on the CD 55 is read at a predetermined rate two or moretimes as fast as the standard data rate prescribed for the CD 55. Theread-out audio data is digital audio data according to PCM (Pulse CodeModulation). Hereinafter, this digital audio data will be referred to asPCM data. In the CD-ROM drive 9, the PCM data is read out of the CD 55in units of frames (2368 bytes including a 16-byte header). Then, theread PCM data is supplied to the DRAM 11 via the bus 40 in step S50. ThePCM data stored in the DRAM 11 is read in frame. At this time, the16-byte header is extracted and the PCM data is read out of the DRAM 11in units of 2352 bytes. The read-out PCM data is supplied to thecompression encoder 12 via the bus 40 in step S51.

In this embodiment, the compression encoder 12 employs the ATRAC methodfor compression. The PCM data supplied to the compression encoder 12 iscoded and compressed in accordance with the ATRAC method. Hereinafter,the data coded and compressed in accordance with the ATRA method will bereferred to as ATRAC data.

The ATRAC data is outputted from the compression encoder 12 in units ofblocks comprising 424 bytes and is supplied to the DRAM 11 via the bus40 in step S52. When 77 blocks of the ATRAC data are accumulated in theDRAM 11, the accumulated data is outputted as a block of 32 kbytes as awhole after being added with a 120-byte header. This block is suppliedto the HDD 10 from the DRAM 11 via the bus 40 and written in the HDD 10in step S53.

FIG. 12 is a flowchart showing a data flow in the processing forequi-rate playback of the CD 55. First, the CD 55 is loaded in theCD-ROM drive 9, and the PCM data recorded on the CD 55 is read at thestandard data rate prescribed for the CD 55 in step S60. The PCM data isread out of the CD 55 in frame units, that is, 2368 bytes including a16-byte header. Then, the read-out PCM data is supplied in frame unitsto the D/A converter 22 via the bus 40 in step S61. Incidentally, sincethe PCM data recorded on the CD 55 is not subjected to thecompression-coding process, the decompressing process by the compressiondecoder shown in FIG. 2 is not performed in this case.

The PCM data is converted by the D/A converter 22 into an analog audiosignal and is reproduced as sounds through the speaker 24 after beingamplified to a predetermined level by the amplifier 23.

In the above-described reproducing and writing processes, the presentinvention is intended to perform the high-rate writing into the HDD 10and the reproduction at the equi-rate simultaneously. To this end, alarge amount of the PCM data reproduced from the CD 55 for writing intothe HDD 10 is stored in the DRAM 11 prior to the high-rate writing, andthe stored PCM data is read in units of small amounts for playback. Thismethod enables the CPU to access the other audio data of the CD 55.

The reproducing and writing processes executed when the high-ratewriting into the HDD 10 is performed while effecting playback of the CD55, will be first described in more detail with reference to flowchartsof FIGS. 13A, 13B and 14A, 14B. FIGS. 13A and 13B show the reproducingprocess. Specifically, FIG. 13A shows main processing of the playbackprocess executed by the CPU 8, and FIG. 13B shows processing executedwhen an interrupt is caused in the main processing shown in FIG. 13A.

Referring to FIG. 13A, when the CD 55 is loaded in the CD-ROM drive 9and the system is ready for writing the PCM data of the CD 55 in the HDD10, the D/A converter 22 is first set to the playback mode in step S100,whereby the system is brought into a state capable of converting thesupplied PCM data into an analog signal. In next step S101, a not-shownDMA (Direct Memory Access) controller for controlling the DRAM 11 forplayback is set into an operation start state.

In step S102, the CD 55 is played back and a predetermined amount of thePCM data reproduced from the CD 55 is transmitted to the DRAM 11 andstored in a playback data area of the DRAM 11. Then, the PCM data isread out of the DRAM 11 and supplied to the D/A converter 22. In nextstep S103, the CPU 8 waits for an interrupt indicating that the PCM datastored in the DRAM 11 for playback has been all read out of the same.For example, the DRAM 11 is always monitored by a DMA controller forcontrolling the DMA, and an interrupt is generated to the CPU 8 when afree space of the playback data area exceeds a predetermined value.

Upon reaching step S103 where the CPU 8 waits for an interrupt, theprocess goes to a playback interrupt flow shown in FIG. 13B. When theDMA controller generates an interrupt to the CPU 8 in step S104representing an interrupt standby state, the process goes to step S105where it is determined whether the playback data from the CD 55 has runout. If not run out, the process goes to step S106 where a predeterminedamount of the PCM data reproduced from the CD 55 is transferred to theDRAM 11 and stored in the playback data area prepared within the DRAM11. Then, the PCM data stored in the DRAM 11 is read out of the DRAM 11and supplied to the D/A converter 22.

The processing to write the PCM data reproduced from the CD 55 in theHDD 10 will be described with reference to FIGS. 14A and 14B. FIG. 14Ashows main processing of the writing process executed by the CPU 8, andFIG. 14B shows processing executed when an interrupt is caused in themain processing shown in FIG. 14A. Referring to FIG. 14A, when the CD 55is loaded in the CD-ROM drive 9 and the system is ready for writing thePCM data of the CD 55 in the HDD 10, the compression encoder 12 is firstset to an operation start state in step S110, whereby the system isbrought into a state capable of coding and compressing the supplied PCMdata.

In next step S111, a not-shown DMA controller is set into an operationstart state for transferring the ATRAC data, coded and compressed by thecompression encoder 12, from the DRAM 11 to the HDD 10. Then, in stepS112, another not-shown DMA is set into an operation start state fortransferring the PCM data, reproduced from the CD 55 and stored in theDRAM 11, to the compression encoder 12 from the DRAM 11.

In next step S113, the CD 55 is played back and a predetermined amountof the PCM data reproduced from the CD 55 is transmitted to the DRAM 11and stored in a write data area of the DRAM 11. Then, in step S114, theCPU 8 waits for an interrupt indicating that the PCM data stored in theDRAM 11 for recording has been all read out of the same. As describedabove, the DRAM 11 is always monitored by the DMA controller, and aninterrupt is generated to the CPU 8 when a free space of the write dataarea exceeds a predetermined value.

Upon reaching step S114 where the CPU 8 waits for an interrupt, theprocess goes to a writing interrupt flow in FIG. 14B. When the DMAcontroller generates an interrupt to the CPU 8 in step S115 representingan interrupt standby state, the process goes to step S116 where it isdetermined whether the write data from the CD 55 has run out.

If it is found in step S116 to be not run out, the process goes to stepS117. In step S117, a predetermined amount of the PCM data reproducedfrom the CD 55 is transferred to the DRAM 11 and stored in the writedata area prepared, for example, within the DRAM 11. Then, the PCM datastored in the DRAM 11 is read out of the DRAM 11 and supplied to thecompression encoder 12.

On the other hand, if it is determined in step S116 that the supply ofthe write data from the CD 55 has completely ended, the process goes tostep S118 where the compression encoder 12 is set into an operation endstate. The writing process from the CD 55 to the HDD 10 is therebyended.

Additionally, the above-described playback interrupt process and writinginterrupt process are set such that the playback interrupt process hashigher priority than the writing interrupt process. Also, the mainprocessing of the writing process shown in FIG. 14A is controlled to bestarted after the main processing of the playback process shown in FIG.13A has entered the interrupt standby state.

FIG. 15 is a sequence chart showing one example of data flows in variouscomponents in more detail. Sequences shown in FIG. 15 correspondrespectively to steps S50-S53, S60 and S61 described above. First, thePCM data for playback is read out of the CD 55 by high-rate reproductionfor 10 seconds and accumulated in the DRAM 11 (SEQ70). The PCM dataaccumulated in the DRAM 11 is read in small amounts. The read PCM datais supplied to the D/A converter 22 and reproduced to sounds after beingconverted into an analog signal (SEQ71). At the timing at which the PCMdata accumulated in the DRAM 11 for 10 seconds has been all read, a nextset of the PCM data is read out of the CD 55 (SEQ72).

FIG. 15 shows reading the data out of the DRAM 11 only one time insequence SEQ71. In fact, however, the data is read out of the DRAM 11several times at appropriate timing until sequence SEQ72. Reading of thePCM data out of the DRAM 11 for playback is performed with priority sothat reproduced sounds will not break off. Additionally, the term “PCMdata for 10 seconds” means the PCM data that lasts for a playback timeof 10 seconds when reproduced to sounds.

During the period in which playback is performed in above sequencesSEQ70 and SEQ71, processing to read the PCM data out of another locationon the CD 55 and to write the read data in the HDD 10 is performed inparallel. After the PCM data has been read out of the CD 55 in abovesequence SEQ70, the PCM data to be written in the HDD 10 is read out ofthe CD 55 by next sequence SEQ80. The read PCM data is sent to thecompression encoder 22 in sequence SEQ81 for the compression-coding. TheATRAC data resulted from coding and compressing the PCM data isaccumulated in the DRAM 11 in sequence SEQ82. When the ATRAC data of 32kbytes including a predetermined header is accumulated in the DRAM 11,the accumulated ATRAC data is read out of the DRAM 11 and the read ATRACdata is sent to the HDD 10 for writing.

FIG. 15 is illustrated as executing sequence SEQ82 only one timecorresponding to sequence SEQ81. In fact, however, since the ATRAC datais sent in units of 424 bytes from the compression encoder 22 to theDRAM 11 as described above, sequence SEQ82 is repeated 77 times.

On the other hand, when the PCM data accumulated in the DRAM 11 forwriting in above sequence SEQ81 is all read, a next set of the PCM datasubsequent to the PCM data, which has been read out of the CD 55 inabove sequence SEQ80, is read out of the CD 55 in sequence SEQ84 andaccumulated in the DRAM 11. When the compression-coding of the PCM databy the compression encoder 22 in above sequences SEQ81 and SEQ82 isended, the PCM data having been accumulated in the DRAM 11 in sequenceSEQ84 is sent to the compression encoder 22 (SEQ85). Then, the ATRACdata coded and compressed by the compression encoder 22 is accumulatedin the DRAM 11 in sequence SEQ86. When a predetermined amount of theATRAC data is accumulated in the DRAM 11, the accumulated ATRAC data isread out of the DRAM 11 and written in the HDD 10 in sequence SEQ87.

Also, when the PCM data accumulated in the DRAM 11 in sequence SEQ85 issent to the compression encoder 22, a next set of the PCM data is readout of the CD 55 and accumulated in the DRAM 11 (SEQ88). When transferof the ATRAC data from the compression encoder 22 to the DRAM 11 insequence SEQ86 is ended, the PCM data accumulated in the DRAM 11 is sentfrom the DRAM 11 to the compression encoder 22.

By repeating the above-described sequences, it is possible to reproducethe PCM data read out of the CD 55, and at the same time to read the PCMdata from another location on the CD 55 and write the read data in theHDD 10 after the compression-coding. These reproducing and writingprocesses can be automatically performed by executing the processeswhile confirming flags indicating that transmission of the respectivedata has been ended.

A description is now made of control of the CD-ROM drive 9 during theprocessing shown in FIG. 15. FIG. 16 shows one example of data amountsread out of the CD 55 by one read in the reproducing and writingprocesses. It is assumed that the playback time of one piece of music is52 seconds and the compression-coding process can be executed 10 timesduring 10 seconds corresponding to one read for playback. The numbersassigned to respective sets of data shown in FIG. 16 represent oneexample of the order in which the sets of data are read.

The data of 52 seconds is read out of the CD 55 for playback in units of10 seconds as indicated by the PCM data (1), (12), (20), (21) and (22)at A in FIG. 16. The data (23) represents the remaining data of 2seconds. On the other hand, for writing into the HDD 10, the data isread out of the CD 55 in units of length corresponding a time requiredfor the compression encoder 12 to execute the compression-codingprocess, as indicated by the PCM data (2)-(11) and (13)-(19) at B inFIG. 16.

FIG. 17 shows, on the time base, one example of reading of the PCM datafrom the CD 55. As indicated by the numbers in FIG. 17 corresponding tothose in FIG. 16, the PCM data (1) for playback is first read out of theCD 55 for 10 seconds and stored in the DRAM 11. While the PCM data (1)is being reproduced, the PCM data (2), (3), (4), . . . , (11) areintermittently read for writing into the HDD 10. The PCM data (2)-(11)are stored in the DRAM 11 whenever each set of data is read, and thenwritten in the HDD 10 after being subjected to the compression-coding.Corresponding to the timing at which the reproduction of the PCM data(1) previously read for playback is ended, the PCM data (12) of next 10seconds is read out of the CD 55 for subsequent playback.

In the above description, the PCM data of 10 seconds is stored in theDRAM 11 for playback. If the DRAM 11 has a sufficient capacity, however,a larger amount of the PCM data may be stored in the DRAM 11.Conversely, a smaller amount of the PCM data corresponding to 5 or 2seconds, for example, may be stored in the DRAM 11.

Also, although the PCM data reproduced from the CD 55 is written in theHDD 10 in the above description, a recording medium as the writingsource is not limited to the CD 55. By employing drive units adapted forrespective recording media, a small-sized magneto-optical disk with adiameter of about 64 mm or a CD having a recording layer formed of dyesto be able to record data are also usable. Further, a semiconductormemory may be used as a writing source.

A first modification of the embodiment will be described below. In theabove-described embodiment, the PCM data recorded on the CD 55 is storedin the HDD 10 while playback of the CD 55 is performed using the PCMdata read out of the CD 55 directly as it is. In this firstmodification, the PCM data read out of the CD 55 is written in the HDD10 after being subjected to the compression-coding, and the ATRAC datawritten in the HDD 10 is decoded for reproduction when playback of theCD 55 is to be performed in parallel with the writing into the HDD 10.

For decoding the data that has been reproduced from the CD 55 andwritten in the HDD 10 after being subjected to the compression-coding,this first modification has a different data flow from theabove-described embodiment. FIG. 18 shows one example of constructionadaptable for the first modification. The compression decoder 21 isadded to the construction of FIG. 10. Note that components in FIG. 18corresponding to those in FIG. 10 are denoted by the same numerals and adetailed description thereof is not repeated here.

The high-rate writing into the HDD 10 is executed in the same manner asthe above-described processing shown in FIG. 11, and therefore thehigh-rate writing process is not described here.

A data flow in the reproducing process executed in parallel with thehigh-rate writing into the HDD 10 will be described below with referenceto a flowchart of FIG. 19. First, the ATRAC data written in the HDD 10is read out of the HDD 10 in units of 32 kbytes and stored in the DRAM11 step S70. Then, the ATRAC data stored in the DRAM 11 is read out ofthe DRAM 11 in units of 424 bytes and supplied to the compressiondecoder 21 (step S71). Subsequently, the PCM data resulted from decodingof the ATRAC data by the compression decoder 21 is stored in the DRAM 11in units of 2352 bytes in step S72. The PCM data is read out of the DRAM11 in units of 2352 bytes and supplied to the D/A converter 22 forconversion into an analog audio signal in step S73.

FIG. 20 is a sequence chart showing one example of data flows in variouscomponents of the first modification in more detail. Sequences shown inFIG. 20 correspond respectively to steps S50-S53 and S70-S73 describedabove. In this first modification, the processing to reproduce the PCMdata from the CD 55 at a high data rate and write the reproduced PCMdata in the HDD 10 after the compression-coding thereof is executed inthe same manner as the above-described one shown in FIG. 15.

The reproducing process in parallel with the writing into the HDD 10 isexecuted in this first modification as follows. The reproducing processis started after the PCM data reproduced from the CD 55 by firstsequence SEQ80 has been subjected to the compression-coding and theresulting compressed data has been written in the HDD 10 in sequenceSEQ83′. After sequence SEQ83′, the ATRAC data written in the HDD 10 isread in sequence SEQ90 and stored in the DRAM 11. The ATRAC data storedin the DRAM 11 is read in sequence SEQ91 and supplied to the compressiondecoder 21. The ATRAC data supplied to compression decoder 21 is decodedinto PCM data which is then stored in the DRAM 11 in sequence SEQ92. ThePCM data stored in the DRAM 11 is read at appropriate timing in sequenceSEQ93 and supplied to the D/A converter 22.

In the above sequences, the processing of the sequence SEQ93 (step S73)is set to have top priority so that reproduced sounds will not breakoff. To this end, when the PCM data stored in the DRAM 11 to be read forstep S73 has become smaller than a predetermined amount, the processingof steps S70-S72 is executed upon an interrupt generated during thewriting process of steps S50-S53.

A second modification of the embodiment will be described below. In thissecond modification, audio data is provided as having been subjected tothe compression-coding in advance and recorded on a recording or storagemedium such as a CD-ROM, and the audio data is read out of the CD-ROMfor writing into the HDD 10. In the following description, it is assumedthat the audio data recorded on the CD-ROM is coded and compressed usingthe compression-coding method in accordance with Layer 3 of the MPEG 1(Moving Picture Experts Group 1), hereinafter referred to as MP3. Inother words, audio data, hereinafter referred to as MP3 data, havingbeen coded and compressed in accordance with MP3 beforehand is recordedon a CD-ROM, for example, and then supplied to the user. The user canobtain an analog audio signal through steps of decoding the MP3 dataread out of a CD-ROM into PCM data and D/A-converting the PCM data intoan analog audio signal.

FIG. 21 shows one example of construction adaptable for the secondmodification. This construction differs from the construction of FIG. 10in that an encoder/decoder 300 for decoding the MP3 data and for codingand compressing the PCM data in accordance with the MP3 method isemployed instead of the compression decoder 21 for performing thedecoding process in accordance with the ATRAC method. Note thatcomponents in FIG. 21 corresponding to those in FIG. 10 are denoted bythe same numerals and a detailed description thereof is not repeatedhere.

FIG. 22 is a flowchart showing one example of a data flow in the writingprocess. First, a CD-ROM including MP3 data recorded thereon is loadedin the CD-ROM drive 9, and the MP3 data recorded on the CD-ROM is read.Then, the read MP3 data is supplied to the DRAM 11 via the bus 40 andstored in the DRAM 11 in step S80. The MP3 data is read out of the DRAM11 and supplied to the encoder/decoder 300 in step S81.

PCM data resulted from decoding of the MP3 data by the encoder/decoder300 is supplied to the DRAM 11 in step S82. The PCM data read out of theDRAM 11 is supplied to the encoder/decoder 300 again in step S83 forcompression-coding into ATRAC data. The ATRAC data is supplied from theencoder/decoder 300 to the DRAM 11 in step S84. The ATRAC data read outof the DRAM 11 is written in the HDD 10 in units of 32 kbytes in stepS85.

As an alternative, the MP3 data read out of the CD-ROM may be directlywritten in the HDD 10 without being subjected to decoding andcompression-coding in accordance with the ATRAC method. In this case, asshown in FIG. 23 by way of example, the MP3 data read out of the CD-ROMis supplied to the DRAM 11 in step S86, and when the MP3 data of 32kbytes is accumulated in the DRAM 11, the MP3 data is read out of theDRAM 11 and written in the HDD 10 in step S87.

FIG. 24 is a flowchart showing a data flow in the reproducing process ofthe MP3 data recorded on the CD-ROM. First, the MP3 data recorded on theCD-ROM is read out of the CD-ROM and stored in the DRAM 11 in step S90.Then, the MP3 data stored in the DRAM 11 is read therefrom and suppliedto the encoder/decoder 300 in step S91. PCM data resulted from decodingof the MP3 data by the encoder/decoder 300 is stored in the DRAM 11 instep S92. The PCM data read out of the DRAM 11 is supplied to the D/Aconverter 22 for conversion into an analog audio signal in step S93.

FIG. 25 is a sequence chart showing one example of data flows in variouscomponents in more detail according to the second modification. FIG. 25represents the case where the MP3 data recorded on a CD-ROM is decodedinto PCM data, and the PCM data is coded and compressed in accordancewith the ATRAC method for writing into the HDD 10. Accordingly,sequences shown in FIG. 25 correspond respectively to steps S80-S85 andS90-S93 described above. Further, in FIG. 25, the encoder/decoder 300 isshown as being separated into an encoder and a decoder for the sake ofconvenience.

In the reproducing process, the MP3 data read out of the CD-ROM isstored in the DRAM 11 in sequence SEQ100. The MP3 data is read out ofthe DRAM 11 and supplied to the decoder in sequence SEQ101. The PCM dataresulted from decoding of the MP3 data by the decoder is stored in theDRAM 11 in sequence SEQ102. When a predetermined amount of the PCM datais stored in the DRAM 11, the PCM data is read out of the DRAM 11 andsupplied to the D/A converter 22 in sequence SEQ103. This sequenceSEQ103 is executed at appropriate timing so that reproduced sounds willnot break off.

When the MP3 data stored in the DRAM 11 is all read in above sequenceSEQ101, a next set of the MP3 data is read out of the CD-ROM and storedin the DRAM 11 in sequence SEQ104. After the end of the decoding processby the decoder in above sequence SEQ102, the read MP3 data is suppliedto the decoder in sequence SEQ105.

In the writing process, when the PCM data is supplied to the D/Aconverter 22 and reproduction into an analog audio signal is started inabove sequence SEQ103, the MP3 data read out of the CD-ROM is stored inthe DRAM 11 in sequence SEQ110. Then, the MP3 data stored in the DRAM 11is read and supplied to the decoder for decoding into PCM data insequence SEQ111. The PCM data resulted from decoding of the MP3 data isstored in the DRAM 11 in sequence SEQ112. The stored PCM data is readout of the DRAM 11 and supplied to the encoder in sequence SEQ113. Theread-out PCM data is coded and compressed into ATRAC data by the encoderand stored in the DRAM 11 in sequence SEQ114. Then, the ATRAC datastored in the DRAM 11 is read out of the DRAM 11 and written in the HDD10 in sequence SEQ115.

When the MP3 data stored in the DRAM 11 is all read in sequence SEQ111,a next set of the MP3 data is read out of the CD-ROM and stored in theDRAM 11 in sequence SEQ116. Thereafter, a next series of processsequences are executed in a similar manner subsequent to the end of aprevious series of process sequences.

In the above sequences, the processing of the sequence 103 (step S93) isset to have top priority so that reproduced sounds will not break off.To this end, when the MP3 data stored in the DRAM 11 to be read for stepS93 has become smaller than a predetermined amount, the processing ofsteps S90-S92 is executed upon an interrupt generated during the writingprocess of steps S80-S85.

In the above description, the present invention is applied to the musicserver 50. The present invention is not limited to such an application,however, but also applicable to portable recording and playback units.For example, the portable recording and playback unit 170 shown in FIG.6 is employed as one example of portable recording and playback units,and when high-rate writing from the CD 55 is performed in the musicserver 50, the contact terminal 200 b is selected in the switch circuit200 of the portable recording and playback unit 170 connected to themusic server 50. The audio data read out of the CD 55 and beingsubjected to the compression-coding is thus written in the HDD/flash RAM106 a through the interfaces 34, 35 and the switch circuit 200. The usercan also enjoy sounds reproduced from the CD 55 while the audio data istransferred from the music server 50 to the portable recording andplayback unit 70.

Further, in the above description, the audio data is written in the HDD10 using one kind of compression-coding in any of the embodiment, thefirst modification and the second modification. The present invention isnot limited to such an example, however, and a plurality of differentcompression-coding methods may be optionally selected. Specifically,plural types of compression encoders and compression decoders areprovided in the music server 50 to be adapted for plural kinds ofcompression-coding methods so that a desired one may be selected fromamong those compression-coding methods. Then, when the audio data iswritten in the HDD 10, the audio data is coded and compressed inaccordance with the selected compression-coding method. In this case, aflag representing the selected compression-coding method is recorded ina predetermined area of the HDD 10 in association with the audio datawritten in the HDD 10 after being subjected to the compression-coding.

In the reproducing process, the compression-coding method employed inthe writing process is automatically determined based on the flag set inassociation with the data to be reproduced, and the correspondingcompression decoder is selected for decoding of the data.

Next, a description will be made of the foregoing embodiment and thefirst and second modifications thereof with reference to the drawingswritten over so as to more clearly represent a signal flow. Further, adescription will be made of third, fourth and fifth modifications of theforegoing embodiment. FIGS. 26, 27 and 28 are functional block diagramsof the foregoing embodiment and the first and second modificationsthereof, each diagram showing primarily signal flows. Also, FIGS. 29, 30and 31 are functional block diagrams of the third, fourth and fifthmodifications of the foregoing embodiment, each diagram showingprimarily a signal flow.

FIG. 26 is a functional block diagram of the music server of theembodiment, showing primarily a signal flow. FIG. 26 corresponds to FIG.10. As also described above, PCM data read out of the CD 55 at a highbit rate in amount corresponding to a playback time of several seconds,for example, is accumulated in a DRAM 11A. The accumulated PCM data isread out of the DRAM 11A in units of blocks prescribed for the CD 55,and is converted into an analog audio signal by the D/A converter 22.Sounds are then reproduced by the speaker 24 through the amplifier 23,not shown in FIG. 26.

On the other hand, during the period from a previous read of the PCMdata for playback from the CD 55 as described above to a next read forplayback, reading of the PCM data for writing is performed underpredetermined address control and the read PCM data is accumulated in aDRAM 11B. The PCM data accumulated in the DRAM 11B is read out little bylittle corresponding to the bit rate of the compressing process in thecompression encoder 12. It is here assumed that the compression encoder12 codes and compresses the PCM data in accordance with the ATRACmethod. The compressed audio data having been subjected to thecompression-coding in the compression encoder 12 is accumulated in aDRAM 11C. When a predetermined amount of the compressed audio datacorresponding to the data write unit set for the HDD 10 is accumulatedin the DRAM 11C, the compressed audio data corresponding to the datawrite unit set for the HDD 10 is read out of the DRAM 11C and written inthe HDD 10.

The DRAMs 11A, 11B and 11C may be allocated as different areas of oneDRAM 11.

In practice, the CD-ROM drive 9, not shown in FIG. 26, for playing backthe CD 55, the DRAMs 11A, 11B and 11C, the compression encoder 12, theD/A converter 22, and the HDD 10 are connected to one data bus. Thisdata bus is connected through a bridge circuit to a control bus to whichthe CPU 8, not shown in FIG. 26, is connected. A DMA controller isprovided in each of the CD-ROM drive 9, the compression encoder 12, theD/A converter 22, and the HDD 10.

The data-bus usage right is acquired by any of the respective DMAs inthe CD-ROM drive 9, the compression encoder 12, the D/A converter 22,and the HDD 10, the DMAs being controlled by the CPU so as tosynchronize with each other under the task management of a real time OS(Operating System) described later. Based on the task management, thoughdescribed later in detail, the write and read timings of the DRAMs 11A,11B and 11C and the HDD 10, as well as the timings of other processing,are controlled.

The DRAMs 11A, 11B and 11C are each made up of two banks such that whenone of the two banks is in a write enable state, the other is in a readenable state. Thus, each DRAM can perform write and read in parallel.The two banks are used under the task management in synchronous relationto each other with the aid of status flags indicating Full and Emptystates. As a result, the switch timing between the two banks in each ofthe DRAMs 11A, 11B and 11C, and the timings of reading and writing datafrom and in each DRAM are controlled in a predetermined manner.

For example, while data is written in one bank of the DRAM 11A, data canbe read out of the other bank. When the writing in the one bank orreading from the other bank is ended, both the banks are switched overunder predetermined timing control so that next data is written in theother bank and the data in the one bank is read out.

Note that the bus configuration and the scheme of the task management,described above, are in common with the music servers shown in FIGS. 26to 31.

FIG. 27 is a functional block diagram of the music server according tothe first modification of the embodiment, showing primarily a signalflow by way of example. FIG. 27 corresponds to FIG. 18. In the firstmodification, PCM data read out of the CD 55 at a high bit rate iswritten in the HDD after being subjected to compression-coding. Inparallel with the writing, the compressed audio data written in the HDDis decompressed to obtain a playback output.

More specifically, PCM data read out of the CD 55 at a high bit rate isaccumulated in a DRAM 401A. The accumulated PCM data is read out of theDRAM 401A depending on the data processing unit set for the compressionencoder 12, and is supplied to the compression encoder 12 for coding andcompressing the PCM data by the ATRAC method, for example. The PCM datais coded and compressed in the compression encoder 12, and resultingcompressed audio data is outputted and accumulated in a DRAM 401B. Whena predetermined amount of the compressed audio data corresponding to thedata write unit set for the HDD 10 is accumulated in the DRAM 401B, thecompressed audio data is read out and supplied to the HDD 10 for writingtherein.

On the other hand, the compressed audio data written in the HDD 10through the above-described writing process is read out of the HDD 10 inparallel with the writing process. For example, during the period inwhich the compressed audio data is accumulated in the DRAM 401B inamount corresponding to the data write unit set for the HDD 10, thecompressed audio data is read out of the HDD 10. The compressed audiodata read out of the HDD 10 is accumulated in a DRAM 401C. Thecompressed audio data accumulated in the DRAM 401C is read out in unitsof amount corresponding to the data processing unit set for thecompression decoder 21, and is supplied to the compression decoder 21.

The compressed audio data supplied to the compression decoder 21 isdecompressed and outputted as PCM data. The PCM data outputted from thecompression decoder 21 is accumulated in a DRAM 401D. The PCM dataaccumulated in the DRAM 401D is read out at a predetermined bit ratecorresponding to the conversion bit rate of the D/A converter 22. Theread-out PCM data is converted into an analog audio signal by the D/Aconverter 22 and reproduced as sounds through the speaker 24.

As with the example of FIG. 26, the DRAMs 401A-401D are each made up oftwo banks such that reading of data from one bank and writing of data inthe other bank are executed in parallel with each other. The timings ofreading and writing data from and in the CD-ROM drive 9, the HDD 10 andthe DRAMs 401A-401D are controlled in a predetermined manner under thetask management synchronized among the respective DMAs provided in thosecomponents. As a result, the compressed audio data is written in the HDD10 in a predetermined manner while ensuring that the analog audio signaloutputted from the D/A converter 22 will not break off. The DRAMs401A-401D may be allocated as different areas of one DRAM 401 orconstituted by four separate DRAMs.

FIG. 28 is a functional block diagram of the music server according tothe second modification of the embodiment, showing primarily a signalflow by way of example. FIG. 28 corresponds to FIG. 21. In the secondmodification, compressed audio data inputted in the format coded andcompressed by a fist compression-coding method is decompressed andreproduced. Also, the decompressed PCM data is compressed by a secondcompression-coding method and written in the HDD 10.

It is assumed, for example, that the first compression-coding method isMP3 and the second compression-coding method is ATRAC. For the sake ofbrevity, in the following description, the compression encoder 12 forcoding and compressing PCM data by the ATRAC method is called the ATRACencoder 12 and the compression decoder 21 for decompressing thecompressed PCM data by the same method is called the ATRAC decoder 21.Similarly, an encoder for coding and compressing data by the MP3 methodis called an MP3 encoder and a decoder for decompressing the compresseddata by the same method is called an MP3 decoder.

Audio data coded and compressed by the MP3 method (referred to as MP3data hereinafter) is supplied in the form recorded on, e.g., a CD-ROM404. The MP3 data read out of the CD-ROM 404 is accumulated in a DRAM402A. When the MP3 data is accumulated in the DRAM 402A in amountcorresponding to the data processing unit set for a MP3 decoder 403, theMP3 data accumulated in the DRAM 402A is read out and supplied to theMP3 decoder 403. The MP3 data is decompressed by the MP3 decoder 403 andoutputted as PCM data, which is then accumulated in a DRAM 402B.

When the PCM data is accumulated in the DRAM 402B in amountcorresponding to the data processing unit set for the ATRAC encoder 12,the accumulated PCM data is read out of the DRAM 402B and supplied tothe ATRAC encoder 12. The PCM data is coded and compressed by the ATRACencoder 12, and resulting ATRAC data is accumulated in a DRAM 402C. Whena predetermined amount of the ATRAC data corresponding to the data writeunit set for the HDD 10 is accumulated in the DRAM 402C, the accumulateddata is read out and supplied to the HDD 10 for writing therein.

On the other hand, the PCM data accumulated in the DRAM 402B is alsoread out in parallel with the above writing process. The read PCM datais supplied to the D/A converter 22 for conversion into an analog audiosignal, and reproduced as sounds by the speaker 24, for example, throughthe amplifier 23, not shown in FIG. 28.

As with the examples of FIGS. 26 and 27, the DRAMs 402A-402C are eachmade up of two banks. In the DRAM 402B, for example, while one bank isset to a state of reading data out of it, the other bank is set to awrite enable state. The PCM data supplied from the MP3 decoder 403 isaccumulated in one bank of the DRAM 402B. In parallel, from the otherbank of the DRAM 402B, the PCM data is read in units of amountcorresponding to the data processing unit set for the ATRAC encoder 12and is supplied to the ATRAC encoder 12.

Also, the CD-ROM drive 9, not shown in FIG. 28, is address-controlled ina predetermined manner to read out a part of the MP3 data, which isrecorded on the CD-ROM 404 and used for playback. The read-out MP3 datais processed through the DRAM 402A and the MP3 decoder 403 in thepredetermined manner, and resulting PCM data is accumulated in the otherbank of the DRAM 402B. The PCM data accumulated in the other bank isread out and supplied to the D/A converter 22, while the PCM data forwriting is accumulated in one bank of the DRAM 402B.

The PCM data for writing is read out of the DRAM 402B and supplied tothe ATRAC encoder 12 as described above. Then, The PCM data is coded andcompressed by the ATRAC encoder 12, and resulting ATRAC data isaccumulated in the DRAM 402C. When the ATRAC data is accumulated in theDRAM 402C corresponding to the data write unit set for the HDD 10, theaccumulated ATRAC data is read out of the DRAM 402C in amountcorresponding to the data write unit set for the HDD 10 and is writtenin the HDD 10.

In the second modification, read control from the CD-ROM 404 in theCD-ROM drive 9, control of the DRAMs 402A-402C, and write/read controlof the HDD 10 are carried out with predetermined timing control underthe task management synchronized among the respective DMAs provided inthose components. As a result, the reproducing and writing processes areperformed as described above. It is thus possible to convert MP3 dataread out of the CD-ROM 404 into ATRAC data and write the ATRAC data inthe HDD 10, while processing MP3 data read out of the CD-ROM 404 forplayback.

Additionally, in the second embodiment, the ATRAC data accumulated inthe DRAM 402C is introduced to an output terminal 410 for directoutputting to the exterior.

FIG. 29 is a functional block diagram of the music server according tothe third modification of the embodiment, showing primarily a signalflow by way of example. In the third modification, compressed audio datainputted in the format coded and compressed by a firstcompression-coding method is decompressed. The decompressed PCM data iscoded and compressed by a second compression-coding method, and thenwritten in the HDD 10. In parallel with the above writing process, thecompressed audio data written in the HDD 10 is read and decompressed forplayback.

It is assumed that the first compression-coding method is MP3 and thesecond compression-coding method is ATRAC. Audio data coded andcompressed by the MP3 method is supplied in the form recorded on theCD-ROM 404. The MP3 data read out of the CD-ROM 404 is accumulated in aDRAM 405A. When the MP3 data is accumulated in the DRAM 405A in amountcorresponding to the data processing unit set for the MP3 decoder 403,the MP3 data accumulated in the DRAM 405A is read out and supplied tothe MP3 decoder 403.

The MP3 data is decompressed by the MP3 decoder 403 and resulting PCMdata is accumulated in a DRAM 405B. When the PCM data is accumulated inthe DRAM 405B in amount corresponding to the data processing unit setfor the ATRAC encoder 12, the accumulated PCM data is read out of theDRAM 405B and supplied to the ATRAC encoder 12. The PCM data supplied tothe ATRAC encoder 12 is coded and compressed into ATRAC data, which isthen accumulated in a DRAM 405C. When the ATRAC data is accumulated inthe DRAM 405C in amount corresponding to the data write unit set for theHDD 10, the ATRAC data corresponding to the data write unit set for theHDD 10 is read out of the DRAM 405C and written in the HDD 10.

On the other hand, the ATRAC data written in the HDD 10 is read out ofthe HDD 10 in parallel with the above writing process. For example,during the period in which the ATRAC data is accumulated in the DRAM405C in the amount corresponding to the data write unit set for the HDD10, the ATRAC data is read out of the HDD 10. The ATRAC data read out ofthe HDD 10 is accumulated in a DRAM 405D. The ATRAC data accumulated inthe DRAM 405D is read out in units corresponding to the data processingunit set for the ATRAC decoder 21, and is supplied to the ATRAC decoder21.

The supplied ATRAC data is decompressed by the ATRAC decoder 21 andoutputted as PCM data. The PCM data outputted from the ATRAC decoder 21is accumulated in a DRAM 405E. The PCM data accumulated in the DRAM 405Eis read out at a predetermined bit rate corresponding to the conversionbit rate of the D/A converter 22. The read-out PCM data is convertedinto an analog audio signal by the D/A converter 22 and reproduced assounds through the speaker 24.

As with the examples of FIGS. 26 to 28, the DRAMs 405A-405E are eachmade up of two banks. The timings of reading the ATRAC data from theCD-ROM drive 9 and the HDD 10, as well as the timings of writing andreading data in and from the DRAMs 405A-405E are controlled in apredetermined manner under the task management synchronized among therespective DMAs provided in those components. As a result, the ATRACdata is written in the HDD 10 in a predetermined manner while ensuringthat the analog audio signal outputted from the D/A converter 22 willnot break off.

FIG. 30 is a functional block diagram of the music server according tothe fourth modification of the embodiment, showing primarily a signalflow by way of example. The fourth modification is constructed basicallyin the same manner as the first modification. Specifically, compressedaudio data inputted in the format coded and compressed by a firstcompression-coding method is decompressed. The decompressed PCM data iscoded and compressed by a second compression-coding method, and thenwritten in the HDD 10. In parallel with the above writing process, thecompressed audio data written in the HDD 10 is read and decompressed forplayback.

In the first modification shown, by way of example, in FIG. 27, inparallel with the process of writing data in the HDD 10, the same dataas written in the HDD 10 is read for playback. By contrast, in thefourth modification, different data from that written in the HDD 10 isread out of the HDD 10 for playback.

It is assumed that some ATRAC data is written in the HDD 10 beforehand.PCM data read out of the CD 55 at a high bit rate is accumulated in aDRAM 406A. The accumulated PCM data is read out of the DRAM 406A inunits of amount corresponding to the data processing unit set for theATRAC encoder 12, and is supplied to the ATRAC encoder 12. The suppliedPCM data is coded and compressed by the ATRAC encoder 12, and thenoutputted as ATRAC data. The ATRAC data outputted from the ATRAC encoder12 is accumulated in a DRAM 406B. When a predetermined amount of theATRAC data corresponding to the data write unit set for the HDD 10 isaccumulated in the DRAM 406B, the ATRAC data is read out and supplied tothe HDD 10 for writing therein.

On the other hand, other ATRAC data written in the HDD 10 beforehand isread out of the HDD 10 in parallel with the above writing process. Forexample, during the period in which the ATRAC data is accumulated in theDRAM 406B in amount corresponding to the data write unit set for the HDD10, the other ATRAC data is read out of the HDD 10. The ATRAC data readout of the HDD 10 is accumulated in a DRAM 406C. The ATRAC dataaccumulated in the DRAM 406C is read out at a predetermined bit rate andsupplied to the ATRAC decoder 21.

The ATRAC data supplied to the ATRAC decoder 21 is decompressed andoutputted as PCM data. The PCM data outputted from the ATRAC decoder 21is accumulated in a DRAM 406D. The PCM data accumulated in the DRAM 406Dis read out at a predetermined bit rate corresponding to the conversionbit rate of the D/A converter 22. The read-out PCM data is convertedinto an analog audio signal by the D/A converter 22 and reproducedthrough the speaker 24.

As with the example of FIG. 27, the DRAMs 406A-406D are each made up oftwo banks. The timing of reading the data from the CD-ROM drive 9, notshown in FIG. 30, the timing of writing the data in the HDD 10, thetiming of reading the ATRAC data x from the HDD, as well as the timingsof writing and reading the data in and from the DRAMs 406A-406D arecontrolled in a predetermined manner under the task managementsynchronized among the respective DMAs provided in those components. Asa result, the data can be read and written from and in the HDD 10 in apredetermined manner while ensuring that the analog audio signaloutputted from the D/A converter 22 will not break off.

FIG. 31 is a functional block diagram of the music server according tothe fifth modification of the embodiment, showing primarily a signalflow by way of example. The fifth modification includes a plurality ofcompression encoders and compression decoders corresponding to differentcompression-coding methods, and a selector for selecting input andoutput terminals of the plurality of compression encoders andcompression decoders. The fifth modification having such an arrangementis adaptable for a plurality of compression-coding methods used tocompress audio data supplied from a sound source 420, and enables adesired one of a plurality of compression-coding methods to be selectedto compress PCM data supplied from the sound source 420. Also, the fifthmodification makes it possible to convert the compression-coding methodsused to compress audio data supplied from the sound source 420 intoanother one.

In the music server of FIG. 31, the sound source 420 may be not only theCD 55 or the CD-ROM 404 described above, but also a line input. As analternative, the sound source 420 may be given by reading audio datafrom a semiconductor memory. In this example, PCM, ATRAC, MP3, and AAC(Advanced Audio Coding) are employed as compatible formats of audiodata. As a matter of course, adaptable compression-coding methods arenot limited to those ones. By preparing additional compression encoderand decoders, the audio server can be made adaptable for othercompression-coding methods. For the sake of convenience, it is assumedin the following description that the sound source 420 is supplied asMP3 data recorded on a CD-ROM. The processes of decompressing the MP3data for playback and, in parallel with the reproducing process,converting the MP3 data into ATRAC data for writing in the HDD 10 willbe described below.

Incidentally, as with the examples of FIGS. 26 to 30, DRAMs 421A-421Care each made up of two banks such that when one of the two banks is ina write enable state, the other is in a read enable state.

The MP3 data read out of the sound source 420 is accumulated in one bankof the DRAM 421A. When a predetermined amount of the MP3 data isaccumulated in the one bank of the DRAM 421A, the accumulated MP3 datais read out and supplied to a selector 422A. The selector 422A andlater-described selectors 422B, 423A and 423B are all controlled by acontroller 428. The controller 428 reads header information of the audiodata accumulated in the DRAM 421A and determines, based on the readheader information, whether the audio data is coded and compressed and,if so, which one of the compression-coding methods is employed. Inaccordance with determination results, the controller 428 outputscontrol signals for controlling the selectors 422A, 422B, 423A and 423B.

If the controller 428 determines that the audio data read out of thesound source 420 is coded and compressed by the MP3 method, an outputterminal 422E of the selector 422A is selected. Also, in the example ofFIG. 31 wherein the selectors 423A and 423B have input terminals incommon, a common input terminal 423E is selected. The MP3 data read outof the DRAM 421A is supplied to an MP3 encoder/decoder 426 through theselector 422A. The supplied MP3 data is decompressed by a decoderportion of the MP3 encoder/decoder 426 and outputted as PCM data.

The PCM data outputted from the MP3 encoder/decoder 426 is supplied tothe D/A converter 22 through the selector 423A having the input terminal423E selected. The supplied PCM data is converted into an analog audiosignal and reproduced as sounds through the speaker 24.

During the period in which the data is read out of one bank of the DRAM421A, the MP3 data read out of the sound source 420 is accumulated inthe other bank of the DRAM 421A. Switching-over of the one and otherbanks of the DRAM 421A is controlled at the predetermined timing so thatthe MP3 data accumulated in the other bank is read out in units ofamount corresponding to, e.g., the data processing unit set for the MP3encoder/decoder 426 and is supplied to the MP3 encoder/decoder 426through the selector 422A.

The supplied MP3 data is decompressed by the MP3 encoder/decoder 426into PCM data, which is then accumulated in one bank of the DRAM 421Bthrough the selector 423B having the input terminal 423E selected. Whenthe PCM data is accumulated in the DRAM 421B in amount corresponding to,e.g., the data write unit set for the HDD 10, the PCM data accumulatedin the one bank of the DRAM 421B is read out and written in the HDD 10.

The PCM data written in the HDD 10 through the above-described writingprocess is read out of the HDD 10 in parallel with the writing process.For example, during the period in which a next set of PCM data isaccumulated in the DRAM 421B in amount corresponding to the data writeunit set for the HDD 10, the PCM data written in the HDD 10 through theabove-described writing process is read out. The PCM data read out ofthe HDD 10 is accumulated in one bank of the DRAM 421C.

In this example, as described above, it is assumed that audio data iswritten in the HDD 10 after being subjected to the compression-coding bythe ATRAC method. In FIG. 31, therefore, an output terminal 422D isselected in the selector 422B that has an output terminal in common withthe selector 422A. The PCM data accumulated in the one bank of the DRAM421C is read out in units of amount corresponding to, e.g., the dataprocessing unit set for an encoder portion of an ATRAC encoder/decoder425 and is supplied to the ATRAC encoder/decoder 425 through theselector 422B.

The PCM data supplied to the ATRAC encoder/decoder 425 is subjected tothe compression-coding and resulting ATRAC data is outputted. On thisoccasion, an output terminal 423D of the selector 423B is selectedduring the period in which the PCM data read out of the one bank of theDRAM 421B is written in the HDD 10. Thus, the ATRAC data outputted fromthe ATRAC encoder/decoder 425 is supplied to the DRAM 421B andaccumulated in the other bank thereof. Then, during the period in whichthe PCM data read out of the one bank of the DRAM 421B is not written inthe HDD 10, the ATRAC data is read out of the other bank of the DRAM421B and written in the HDD 10.

In the above processing, the timings of reading and writing the datafrom and in the DRAMs 421A, 421B and 421C, switching-over of theselector 423B, as well as the timings of reading and writing the datafrom and in the HDD 10 are controlled under the task managementsynchronized among the respective DMAs provided in those components, sothat the analog audio signal outputted from the D/A converter 22 willnot break off and the process of writing the data in the HDD 10 isperformed in a predetermined manner.

Additionally, in the fifth embodiment, the data accumulated in the DRAM421B can be introduced to an output terminal 429. With the provision ofthe output terminal 429, the digital audio data accumulated in the DRAM421B can be directly outputted to the exterior through an IEEE 1394interface, for example.

Also, in the above processing, the PCM data outputted from the MP3encoder/decoder 426 and written in the HDD 10 may be erased from the HDD10 after that PCM data has been read out of the HDD 10 and accumulatedin the DRAM 421C.

Further, when writing the data in the HDD 10, the audio data suppliedfrom the sound source 420 may be directly written in the HDD 10 in thesame format by selecting an output terminal 422C in the selector 422Aand an output terminal 423C in the selector 423B.

As mentioned above, the components of the music server according to thepresent invention can be controlled by using a real time operatingsystem (OS). In the following, the real time OS will be brieflydescribed and then a description will be made of the cases where controlusing the real time OS is applied to the above-described embodiment andthe first and fifth modifications thereof.

The real time OS is a multitask OS that is capable of performing aplurality of tasks at the same time and is designed so as to executeprocessing upon an event, that is, an external request, at a maximumspeed. FIG. 32 shows the basic concept of a real time OS applicable forthe present invention. Three states, that is, an operative state, astandby state, and an operation enable state, are assigned to each task.Each task is under the flag management such that a command waitFlag forinstructing the task to wait for a flag is issued when the task shiftsfrom the operative state to the standby state, and a command setFlag forsetting a value to a flag is issued when the task shifts from thestandby state to the operation enable state.

Further, a plurality of tasks can exist at the same time and priorityorders are allocated respectively to the plurality of tasks. The realtime OS transfers the execution right to one of the tasks in theoperation enable state, which has the top priority order.

Thus, the real time OS is designed to be able to switch over the tasksin the operation enable state from one to another at a high speed uponthe occurrence of an event. In this example of the present invention, anevent is produced using only an event flag.

FIG. 33 shows one example of task control for a plurality of tasksexecuted by the real time OS. More specifically, FIG. 33 shows, by wayof example, the case of executing tasks 1, 2 and 3 that are givenrespectively priority orders of “high”, “middle” and “low” by the realtime OS. Flag1 and Flag2 representing respectively the tasks 2 and 3 areeach set to Empty or Full that indicates the status of each task.

The vertical axes in FIG. 33 represents processing executed by the realtime OS, the task 1, the task 2 and the task 3 in that order from leftto right. The actual operation of the CPU executed by the real time OSis represented by solid lines extending between the tasks. Also, theoperative state, the standby state, and the operation enable state ofeach task are indicated respectively by a dotted line, a broken line anda solid line. The CPU monitors the tasks and allocates the tasks so asto execute the following processing based on values of Flag1 and Flag2.

As shown in FIG. 33, the task 1 having the top priority order firstinitializes the flag Flag1 with the value Empty and then initializes theflag Flag2 with the value Empty. Subsequently, the task 1 waits for thevalue Full of the flag Flag2 given by the command waitFlag (Flag2, Full)and then waits for the value Full of the flag Flag1 given by the commandwaitFlag (Flag1, Full). Thereafter, predetermined processing 1 isexecuted. After the execution, the flag Flag2 is set to the value Emptyby the command setFlag (Flag2, Empty) and the flag Flag1 is set to thevalue Empty by the command setFlag (Flag1, Empty). The above processsequence from the command waitFlag (Flag2, Full) to the command setFlag(Flag2, Empty) is repeated until it is completed.

On the other hand, the task 2 having the second priority order next tothe task 1 executes processing 2 after waiting for the value Empty ofthe flag Flag1 given by the command waitFlag. Subsequent to theprocessing 2, the flag Flag1 is set to the value Empty by the commandsetFlag. The above process sequence of the task 2 is repeated until itis completed. A process sequence of the task 3 having the lowestpriority order among the three tasks is similar to that of the task 2.

It is assumed that the above-described conditions are set. First, thetask 1 having the top priority order is brought into the operativestate, and the flags Flag 1 and Flag2 are each set to the value Empty.Then, the command waitFlag (Flag2, Full) is issued.

At this time, the task 2 is created. The task 2 issues the commandwaitFlag (Flag1, Empty). With the flag Flag1 having been initialized tothe value Empty by the task 1, after the task is once returned to thereal time OS, the task 2 executes the processing 2 as a next processstep. After the execution of the processing 2, the command setFlag(Flag1, Full) is issued to set the flag Flag1 to the value Full.

The task is once returned to the real time OS, but the command waitFlag(Flag2, Full) is not yet satisfied. Therefore, the execution right istransferred to the task 2 again and the command waitFlag (Flag1, Empty)is issued. Then, the task is returned to the real time OS, but thecommand waitFlag (Flag2, Full) is not yet satisfied even at this time.Accordingly, the task 2 is brought into the standby state.

Next, the task 3 is created. The task 3 issues the command waitFlag(Flag2, Empty). With the flag Flag2 having been initialized to the valueEmpty by the task 1, after the task is returned to the real time OS, thetask 3 executes the processing 2 as a next process step. After theexecution of the processing 3, the command setFlag (Flag2, Full) isissued to set the flag Flag2 to the value Full. The task 3 transits tothe operation enable state.

The task is returned to the real time OS. Since the command waitFlag(Flag2, Full) is now satisfied by the task 3, a next process step isexecuted in the task 1 and the command waitFlag (Flag1, Full) is issued.The flag Flag1 is satisfied by the task 2, and therefore the task 1executes processing 1 as a next process step. After the execution of theprocessing 1, the command setFlag (Flag2, Empty) is issued and thecommand setFlag (Flag1, Empty) is then issued.

The task 2 has been brought into the state of waiting for the valueEmpty of the flag Flag1, as described above, by the command setFlag(Flag1, Empty) issued after the execution of the processing 2.Accordingly, when the command setFlag (Flag1, Empty) is issued in thetask 1, the task 2 transits to the operation enable state.

In the example of FIG. 33, the process sequence then returns to thebeginning of the loop, whereupon the command waitFlag (Flag2, Full) isissued. Subsequently, the execution right is passed to the task 2 andthe processing 2 is executed.

Thus, in the real time OS applicable to the present invention, theoperations of the tasks are controlled by transferring status flagsbetween the tasks and the real time OS. In this example, one status flagis transferred for each of the tasks. As a result, each task becomessimple and parallel process of multiple tasks can be easily controlledin simple fashion.

Also, in the real time OS applicable to the present invention, thepriority orders are assigned to the tasks as described above. FIG. 34schematically shows one example of the relationship among the tasks whenthe real time OS is applied to the music server according to theembodiment of the present invention. FIG. 34 also indicates the priorityorders assigned to the tasks. It is assumed that the priority orders areassigned using numerals from 0 to 255, for example, and a smallernumeral represents a higher priority order. The priority orders aremanaged by the real time OS.

In the example of FIG. 34, a task KeyTask related to manipulation madeon a control panel of the music server is set to have a top priorityorder assigned with a numeral 10. A task DisplayTask related to displayon the display unit has a priority order assigned with a numeral 150. Atask MMITask related to an MMI (Man Machine Interface) has a priorityorder assigned with a numeral 100. Further, a task StorageTask forhandling writing and reading of compressed or non-compressed audio datain and from a storage medium has a priority order assigned with anumeral 130.

A task CdReadTask related to the process of reading audio data from theCD-ROM drive 9 for writing and writing the audio data in the DRAM 11Bhas a priority order assigned with a numeral 50. A task CoderWriteTaskrelated to the process of supplying the data, which has been written inthe memory by the task CdReadTask, to the compression encoder or thecompression decoder has a priority order that is set a little lower thanthe priority order of the task CdReadTask and assigned with a numeral60, for example.

A task HdWriteTask related to the process of writing the data read outof the DRAM 11C in the HDD 10 has a priority order assigned with anumeral 50. A task CoderReadTask related to the process of writing thedata, which has been outputted from the compression encoder or thecompression decoder, in the memory has a priority order that is set alittle lower than the priority order of the task HdWriteTask andassigned with a numeral 60, for example.

Likewise, a task CdPlayTask related to the process of reading PCM datafrom the CD-ROM drive 9 for playback and writing the PCM data in theDRAM 11A has a priority order assigned with a numeral 50. A taskPcmWriteTask related to the process of reading the PCM data written inthe DRAM 11A and supplying the read PCM data to the D/A converter 22 hasa priority order that is set a little lower than the priority order ofthe task CdPlayTask and assigned with a numeral 60, for example.

Thus, in each set of the tasks related to an access to the DRAM, thatis, in each set of the tasks CdReadTask and CoderReadTask, the tasksHdWriteTask and CoderReadTask, and the tasks CdPlayTask andPcmWriteTask, a higher priority order is assigned to the task requiringa longer processing time.

Further, as indicated by solid and dotted arrows in FIG. 34, requestsand responses are transferred between the tasks. As also seen from FIG.34, each set of the tasks CdReadTask and CoderReadTask, the tasksHdWriteTask and CoderReadTask, and the tasks CdPlayTask andPcmWriteTask, are assigned with higher priority orders than that of thetask StorageTask and executed in parallel. On this occasion, asdescribed above, the real time OS controls the each set of the tasksbased on the flags transferred between the tasks so that the executionsof the tasks are synchronized with each other.

FIG. 35 is a functional block diagram representing the case where thetasks shown in FIG. 34 are allocated to respective components of themusic server of the embodiment described above with reference to FIG.26. Note that, in FIG. 35, components in common with those in FIG. 26are denoted by the same numerals and a detailed description thereof isomitted here. Also, in FIG. 35, the DRAMs 11A, 11B and 11C in FIG. 26are shown as clearly indicating that each DRAM is made up of two banks,i.e., banks D20 and D21, banks D00 and D01, and banks D10 and D11.

Further, the status of each component shown in FIG. 35, that is, thestates of the DRAMs 11A, 11B and 11C, the compression encoder 12, theD/A converter 22, the HDD 10, and the CD-ROM drive 9, not shown in FIG.35, for reading data from the CD 55, area always monitored by the CPU 8.The status of each of the monitored components is reflected on the tasksby the real time OS.

The above-described set of the tasks CdReadTask and CoderReadTask, thetasks HdWriteTask and CoderReadTask, and the tasks CdPlayTask andPcmWriteTask are tasks related to inputting and outputting of data toand from the DRAMs 11A, 11B and 11C, respectively. For example, theinput side of the DRAM 11B is controlled by the task CdReadTask, and theoutput side of the DRAM 11B is controlled by the task CoderReadTask. Theinput side is assigned with a higher priority order than that of theoutput side to make control such that the banks are switched over afterwaiting until a predetermined amount of PCM data is accumulated in onebank of the DRAM 11B. This arrangement is similarly applied to the DRAM11A.

In the DRAM 11C, the input side is controlled by the task CoderReadTaskand the output side is controlled by the task HdWriteTask. The outputside is assigned with a higher priority order than that of the inputside to make control such that the banks are switched over after waitinguntil a compressed audio data is accumulated in one bank of the DRAM 11Cin amount corresponding to the data write unit set for the HDD 10.

FIG. 36 schematically shows process flows among the tasks correspondingto FIGS. 34 and 35. In FIG. 36, the time base is shown as representingthe lapse of time in a direction from top to bottom. Transfer ofrequests and notices between the tasks shown in FIG. 36 is performedunder the task management using the flags as described above withreference to FIG. 33. In other words, the process of transferringrequests and notices between the tasks is controlled by the real time OSbased on the status of the associated flags in accordance with thepriority orders assigned to the tasks.

When the CD 55 loaded in the CD-ROM drive 9 is played back at theequi-rate, playback of the CD 55 loaded in the CD-ROM drive 9 isinstructed upon a playback key input entered by the user made on thecontrol panel. In accordance with the instruction, the event of theplayback key input is noticed from the task KeyTask to the task MMITask(SEQ120). In response to the notice, a playback request for the CD 55 isnoticed from the task MMITask to the task StorageTask (SEQ121).

In response to the playback request, a startup request is noticed fromthe task StorageTask to the task CdPlayTask (SEQ122). The PCM datarecorded on the CD 55 loaded in the CD-ROM drive 9 is read out undercontrol of the CPU 8 in accordance with the task CdPlayTask upon thestartup request. The read-out PCM data is accumulated in the DRAM 11B.Also, in response to the above startup request, another startup requestis noticed from the task CdPlayTask to the task PcmWriteTask (SEQ123).The PCM data is accumulated in the DRAM 11A is supplied to the D/Aconverter 22 in a predetermined manner under control of the taskPcmWriteTask.

Next, a description will be made of the high-rate writing process ofcoding and compressing the PCM data recorded on CD 55 under playback andwriting the compressed PCM data in the HDD 10. After playback of the CD55 is started up as described above, the high-rate writing of the PCMdata is instructed by the user manipulating a high-rate Rec key that isprovided in the control panel to instruct the high-rate writing. Inaccordance with the instruction, the event of the high-rate Rec keyinput is noticed from the task KeyTask to the task MMITask (SEQ130). Inresponse to the notice, a request for starting the high-rate writing isissued from the task MMITask to the task StorageTask (SEQ131). Inresponse to the high-rate writing request, a startup request is sentfrom the task StorageTask to each of the task CdReadTask and the taskHdWriteTask (SEQ132 and SEQ133).

The PCM data for writing is read out of the CD 55 under control of theCPU 8 in accordance with the task CdReadTask to which the startuprequest has been noticed. The read-out PCM data is accumulated in theDRAM 11B, and at the same time, another startup request is noticed fromthe task CdReadTask to the task CoderWriteTask (SEQ134). These taskscontrol the reading of the PCM data from the CD 55 and the supply of theread-out PCM data to the compression encoder 22.

On the other hand, the task HdWriteTask, to which the startup requesthas been noticed, controls the reading of the compressed audio data fromthe DRAM 11C and the writing of the read-out compressed audio data inthe HDD 10. More specifically, upon the startup request being noticed tothe task HdWriteTask, a further startup request is noticed from the taskHdWriteTask to the task CoderReadTask (SEQ136). The compressed audiodata outputted from the compression encoder 12 is accumulated in theDRAM 11C under control of the task CoderReadTask to which the startuprequest has been noticed.

Also, the task HdWriteTask controls the reading of the compressed audiodata from the DRAM 11C. For example, when the compressed audio data isaccumulated in the DRAM 11C in an amount corresponding to the data writeunit set for the HDD 10, the compressed audio data is read out of theDRAM 11C and written in the HDD 10.

When the high-rate writing of the PCM data from the CD 55 is ended, theend of the high-rate writing is noticed from the CPU 8 to the taskCoderWriteTask, and a notice of end indicating the end of the high-ratewriting is passed from the task CoderWriteTask to the task CdReadTask(SEQ136). Under control of the task CdReadTask which has received thenotice of end, the reading of the PCM data from the CD 55 for writing isended, whereupon a notice of end is passed from the task CdReadTask tothe task StorageTask (SEQ138).

The end of the high-rate writing of the PCM data from the CD 55 is alsonoticed from the CPU 8 to the task CoderReadTask. The taskCoderReadTask, which has received the notice, passes the notice of endto the task HdWriteTask (SEQ137). Then, the notice of end is passed fromthe task HdWriteTask, which has received the notice, to the taskStorageTask (SEQ139).

In the task StorageTask, upon receiving the notice of end from each ofthe task CdReadTask and the task HdWriteTask, a notice of end indicatingthe end of the high-rate writing is passed to the task MMITask (SEQ140).

Further, in relation to the reading of the PCM data from the CD 55 forplayback, when the reading of the PCM data from the CD 55 is ended, theend of the reading is noticed from the CPU 8 to the task PcmWriteTask.The task PcmWriteTask, which has received the notice, passes the noticeof end to the task CdPlayTask (SEQ141), and the notice of end is thenpassed from the task CdPlayTask to the task StorageTask (SEQ142).Subsequently, the end of the equi-rate playback of the CD 55 is noticedfrom the task StorageTask to the task MMITask (SEQ143).

The above-described control by the real time OS, in particular, the bankcontrol in the DRAMs 11A, 11B and 11C, will be described in more detailwith reference to flowcharts of FIGS. 37, 38 and 39. FIG. 37 is aflowchart showing one example of processing executed by the taskCdReadTask and the task CoderWriteTask. Specifically, A in FIG. 37 showsthe processing executed by the task CdReadTask and B in FIG. 37 showsthe processing executed by the task CoderWriteTask. Also, in A and B ofFIG. 37, steps S114, S116, S117, S121 and S123 represent the processingexecuted by the real time OS.

In A, when the task CdReadTask receives a startup request from the taskStorageTask, the status flag indicating the state of the DRAM 11B isinitialized in step S110 such that one bank D00 and the other bank D01of the DRAM 11B are each set to the Empty state indicating the relevantbank being empty. Assuming, for example, that the flag of the bank D00is Flag00 and the flag of the bank D01 is Flag01, values of the Flag00and Flag01 are each set to “Empty”.

After the status flags of the banks of the DRAM 11B have beeninitialized, a startup request is issued from the task CdReadTask to thetask CoderWriteTask in step S111. In response to the startup request,the processing shown in flowchart B of FIG. 37 is started. The flowchartof B will be described later.

Then, in A, it is determined in next step S112 whether the PCM data hasbeen completely read out of the CD 55. If the reading is completed, theprocess flow goes to step S117 where the CPU waits for a notice of endfrom the task CdReadTask. Whether the PCM data has been completely readout of the CD 55 is determined, for example, by the CPU 8 monitoring theoperation of the CD 55. A determination result is noticed to the realtime OS.

On the other hand, if it is determined in step S112 that the reading ofthe PCM data out of the CD 55 is not yet completed, the process flowgoes to step S113 where the bank of the DRAM 11B is set to the bank D00.With the bank setting in step S113, the two banks are alternatelyswitched over such that the selected bank is changed in the order ofbank D00, bank D01, bank D00, . . . whenever the processing started fromstep S112 is looped. The PCM data read out of the CD 55 by the taskCdReadTask is accumulated in the bank of the DRAM 11B set in step S113.

In next step S114, the command waitFlag is issued by the taskCdReadTask, and the real time OS waits for until the bank (assumed to beD00) of the DRAM 11B set in step S113 comes to the Empty state. If thebank D00 comes to the Empty state, the process flow goes to step S115.

In step S115, the PCM data is read out of the CD 55 in amountcorresponding to the capacity of the bank (bank D00) of the DRAM 11B setin step S113. The read-out PCM data is DMA-transferred to the bank D00of the DRAM 11B and written in the bank D00.

When the predetermined amount of the PCM data is written in the bankD00, the task CdReadTask issues the command setFlag in next step S116,whereby the status flag of the bank D00 is set to Full. After thecompletion of the flag setting, the process flow returns to step S112.

On the other hand, the processing shown in flowchart B is startedfollowing the processing in above-described step S111. Morespecifically, when the startup request is issued in step S111 to thetask CoderWriteTask, the bank of the DRAM 11B is set to the bank D00 instep 120. With the bank setting in step S120, the two banks arealternately switched over such that the selected bank is changed in theorder of bank D00, bank D01, bank D00, . . . whenever the processing islooped from step S124 described later.

In next step S121, the command waitFlag is issued by the taskCoderWriteTask, and the real time OS waits for until the bank (assumedto be D00) of the DRAM 11B set in step S120 comes to the Full state.Stated otherwise, in step S121, the CPU waits for the end of theprocessing of step S116. If the bank D00 comes to the Full state, theprocess flow goes to step S122.

In step S122, the PCM data is read out of the bank (bank D00) of theDRAM 11B set in step S120 in amount corresponding to the capacity of thebank D00. The read-out PCM data is DMA-transferred to the compressionencoder 12 and written in, for example, a processing memory for thecompression encoder 12.

If the predetermined amount of the PCM data is read out of the bank D00of the DRAM 11B in step S122, the process flow goes to next step S123.In step S123, the command setFlag is issued by the task CoderWriteTaskand the status flag of the bank D00 is set to the Empty state.

After the end of the flag setting, the process flow goes to step S124where it is determined whether the PCM data has been completely read outof the CD 55. If it is determined that the PCM data has not beencompletely read out of the CD 55, the process flow returns to step S120.

On the other hand, if it is determined in step S124 that the PCM datahas been completely read out of the CD 55, a notice of end is passedfrom the task CoderWriteTask to the task CdReadTask, whereby a sequenceof the processing shown in B of FIG. 37 is ended. Then, if the notice ofend from the task CoderWriteTask is received by the task CdReadTask inabove step S117, a sequence of the processing shown in A and B of FIG.37 is ended.

Next, one example of the processing executed by the task HdWriteTask andthe task CoderReadTask with reference to flowcharts of shown at A and Bof FIG. 38. A shows the processing executed by the task HdWriteTask andB shows the processing executed by the task CoderReadTask. Note that inA and B of FIG. 38 steps S134, S136, S137, S141 and S143 represent theprocessing executed by the real time OS.

In A of FIG. 38, when the task HdWriteTask receives a startup requestfrom the task StorageTask, the status flag indicating the state of theDRAM 11C is initialized in step S130 such that one bank D10 and theother bank D11 of the DRAM 11C are each set to the Empty stateindicating the relevant bank being empty.

After the status flags of the banks of the DRAM 11C have beeninitialized, a startup request is issued from the task HdWriteTask tothe task CoderReadTask in step S131. In response to the startup request,the processing shown in flowchart B of FIG. 38 is started. The flowchartof B in FIG. 38 will be described later.

Then, in A, it is determined in next step S132 whether thecompressed-coding of the PCM data by the compression encoder 12 iscompleted and the supply of the compressed audio data from thecompression encoder 12 is completed. If the supply of the compressedaudio data from the compression encoder 12 is completed, the processflow goes to step S137 where the CPU waits for a notice of end from thetask CoderWriteTask. Whether the PCM data has been completely coded andcompressed by the compression encoder 12 is determined, for example, bythe CPU 8 monitoring the operation of the compression encoder 12. Adetermination result is noticed to the real time OS.

On the other hand, if it is determined in step S132 that the supply ofthe compressed audio data from the compression encoder 12 is not yetcompleted, the process flow goes to step S133 where the bank of the DRAM11C is set to the bank D10. With the bank setting in step S133, the twobanks are alternately switched over such that the selected bank ischanged in the order of bank D10, bank D11, bank D10, . . . whenever theprocessing started from step S132 is looped. The compressed audio datawritten in the HDD 10 by the task HdWriteTask is read out the bank ofthe DRAM 11C set in step S133.

In next step S134, the command waitFlag is issued by the taskHdWriteTask, and the real time OS waits for until the bank (assumed tobe D10) of the DRAM 11C set in step S133 comes to the Full state. If thebank D10 comes to the Full state, the process flow goes to step S135.

In step S135, the compressed audio data is read out of the bank (bankD10) of the DRAM 11C set in step S133 in amount corresponding to thecapacity of the bank D10 of the DRAM 11C, and is written in the HDD 10.The compressed audio data read out of the bank D10 of the DRAM 11C isDMA-transferred to the HDD 10.

When the predetermined amount of the compressed audio data is written inthe HDD 10, the task HdWriteTask issues the command setFlag in next stepS136, whereby the status flag of the bank D10 of the DRAM 11C is set toEmpty. After the completion of the flag setting, the process flowreturns to step S132.

On the other hand, the processing shown in flowchart B of FIG. 38 isstarted following the processing in above-described step S131. Morespecifically, when the startup request is issued in step S131 to thetask CoderReadTask, the bank of the DRAM 11C is set to, e.g., the bankD10 in step 140. With the bank setting in step S140, the two banks arealternately switched over such that the selected bank is changed in theorder of bank D10, bank D11, bank D10, . . . whenever the processing islooped from step S144 described later.

In next step S141, the command waitFlag is issued by the taskCoderReadTask, and the real time OS waits for until the bank (assumed tobe D10) of the DRAM 11C set in step S140 comes to the Empty state.Stated otherwise, in step S141, the CPU waits for the end of theprocessing of step S136. If the bank D10 comes to the Empty state, theprocess flow goes to step S142.

In step S142, the compressed audio data is read out of the compressionencoder 12 in amount corresponding to the capacity of the bank (bankD10) of the DRAM 11C set in step S140. The read-out compressed audiodata is DMA-transferred from the compression encoder 12 to the bank D10of the DRAM 11C and is written in the bank D10.

If the predetermined amount of the compressed audio data is written inthe bank D10 of the DRAM 11C in step S142, the process flow goes to nextstep S143. In step S143, the command setFlag is issued by the taskCoderReadTask and the status flag of the bank D10 is set to the Fullstate.

After the end of the flag setting, the process flow goes to step S144where it is determined whether the compressed audio data has beencompletely read out of the compression encoder 12. If it is determinedthat the compressed audio data has not been completely read out of thecompression encoder 12, the process flow returns to step S140.

On the other hand, if it is determined in step S144 that the compressedaudio data has been completely read out of the compression encoder 12, anotice of end is passed from the task CoderReadTask to the taskHdWriteTask, whereby a sequence of the processing shown in B is ended.Then, if the notice of end from the task CoderReadTask is received bythe task HdWriteTask in above step S137, a sequence of the processingshown at A and B in FIG. 38 is ended.

A and B in FIG. 39 are flowcharts showing one example of the processingexecuted by the task CdPlayTask and the task PcmWriteTask. A shows theprocessing executed by the task CdPlayTask and B shows the processingexecuted by the task PcmWriteTask. Note that, in A and B of FIG. 39,steps S154, S156, S157, S161 and S163 represent the processing executedby the real time OS.

In A of FIG. 39, when the task CdPlayTask receives a startup requestfrom the task StorageTask, the status flag indicating the state of theDRAM 11A is initialized in step S150 such that one bank D20 and theother bank D21 of the DRAM 11A are each set to the Empty stateindicating the relevant bank being empty.

After the status flags of the banks of the DRAM 11A have beeninitialized, a startup request is issued from the task CdPlayTask to thetask PcmWriteTask in step S151. In response to the startup request, theprocessing shown in flowchart, B is started. The flowchart B of FIG. 39will be described later.

Then, in A, it is determined in next step S152 whether the playback ofthe CD 55 is completed. If the playback of the CD 55 is completed, theprocess flow goes to step S157 where the CPU waits for a notice of endfrom the task CoderWriteTask. Whether the playback of the CD 55 iscompleted or not is determined, for example, by the CPU 8 monitoring theoperation of the CD 55. A determination result is noticed to the realtime OS.

On the other hand, if it is determined in step S152 that the playback ofthe CD 55 is not yet completed, the process flow goes to step S153 wherethe bank of the DRAM 11A is set to, e.g., the bank D20. With the banksetting in step S153, the two banks are alternately switched over suchthat the selected bank is changed in the order of bank D20, bank D21,bank D20, . . . whenever the processing started from step S152 islooped. The PCM data reproduced from the CD 55 by the task CdPlayTask isaccumulated in the bank of the DRAM 11A set in step S153.

In the next step S154, the command waitFlag is issued by the taskCdPlayTask, and the real time OS waits for until the bank (assumed to beD20) of the DRAM 11A set in step S153 comes to the Empty state. If thebank D20 comes to the Empty state, the process flow goes to step S155.

In step S155, the PCM data is read out of the CD 55 in an amountcorresponding to the capacity of the bank (bank D20) of the DRAM 11A setin step S153. The read-out PCM data is DMA-transferred to the bank D20of the DRAM 11A and written in the bank D20.

When the predetermined amount of the PCM data is written in the bankD20, the task CdPlayTask issues the command setFlag in next step S156,whereby the status flag of the bank D20 is set to Full. After thecompletion of the flag setting, the process flow returns to step S152.

On the other hand, the processing shown in flowchart B is startedfollowing the processing in above-described step S151. Morespecifically, when the startup request is issued in step S151 to thetask PcmWriteTask, the bank of the DRAM 11A is set to the bank D20 instep 160. With the bank setting in step S160, the two banks arealternately switched over such that the selected bank is changed in theorder of bank D20, bank D21, bank D20, . . . whenever the processing islooped from step S164 described later.

In next step S161, the command waitFlag is issued by the taskPcmWriteTask, and the real time OS waits for until the bank (assumed tobe D20) of the DRAM 11A set in step S160 comes to the Full state. Statedotherwise, in step S161, the CPU waits for the end of the processing ofstep S156. If the bank D20 comes to the Full state, the process flowgoes to step S162.

In step S162, the PCM data is read out of the bank (bank D20) of theDRAM 11A set in step S160 in amount corresponding to the capacity of thebank D20. The read-out PCM data is DMA-transferred to the D/A converter22 and written in, for example, a processing memory for the D/Aconverter 22.

If the predetermined amount of the PCM data is read out of the bank D20of the DRAM 11A in step S162, the process flow goes to next step S163.In step S163, the command setFlag is issued by the task PcmWriteTask andthe status flag of the bank D20 is set to the Empty state.

After the end of the flag setting, the process flow goes to step S164where it is determined whether the playback of the CD 55 is completed.If it is determined that the playback of the CD 55 is not completed, theprocess flow returns to step S160.

On the other hand, if it is determined in step S164 that the playback ofthe CD 55 is completed, a notice of end is passed from the taskPcmWriteTask to the task CdPlayTask, whereby a sequence of theprocessing shown at B is ended. Then, if the notice of end from the taskPcmWriteTask is received by the task CdPlayTask in above step S157, asequence of the processing shown in A and B of FIG. 39 is ended.

FIG. 40 shows, in more detail, one example of data flows in variouscomponents during the high-rate writing process for the CD 55 in theembodiment, including bank switching in the DRAMs 11B and 11C. Accordingto the CD-DA standards, PCM data is recorded on the CD 55 in recordunits each defined by one block of 2352 bytes. PCM data of 54 blocks,for example, is read out of the CD 55 by one read. In accordance withthe above-described flowcharts of FIGS. 37 and 38, for each read fromthe CD 55, the PCM data read out of the CD 55 is alternately accumulatedin the banks D00 and D01.

The PCM data accumulated, for example, in the bank D00 of the DRAM 11Bup to the full capacity thereof is read out in units of amountcorresponding to the data processing unit set for the compressionencoder 12 and is supplied to the compression encoder 12. When the PCMdata accumulated in the banks D00 is all read out, the bank of the DRAM11B is switched over from the bank D00 to D01 so that the PCM data iscontinuously read out of the DRAM 11B.

The compression encoder 12 codes and compresses the PCM data that issupplied to it in data processing units, and outputs compressed audiodata having been subjected to the compression-coding at a bit rate setfor the compressed audio data. When the compression encoder 12 codes andcompresses the PCM data by the ATRAC method, resulting ATRAC data isoutputted in units of 424 bytes, for example. The compressed audio dataoutputted from the compression encoder 12 is accumulated in the bank D10of the DRAM 11C.

When the compressed audio data is accumulated in the bank D10 up to thefull capacity thereof which corresponds to the data processing unit setfor the HDD 10, the bank of the DRAM 11C is switched over from the bankD10 to D11 so that the compressed audio data is continuously accumulatedin the DRAM 11C. Then, the compressed audio data accumulated in the bankD10 is read out and written in the HDD 10.

FIG. 41 shows in more detail one example of data flows in variouscomponents during the equi-rate playback of the CD 55 in the embodiment,including bank switching in the DRAM 11A. PCM data corresponding to aplayback time of 3 seconds, for example, is read out of the CD 55. ThePCM data read out of the CD 55 is accumulated, for example, in the banksD20 of the DRAM 11A. When the predetermined amount of the PCM data isaccumulated in the bank D20, the bank of the DRAM 11A, in which the PCMdata is to be accumulated, is switched over from the bank D20 to D21 sothat the PCM data corresponding to next 3 seconds is accumulated in thebank D21. Then, the PCM data is read out of the bank D20 for each blockfor recording in the CD 55, i.e., in units of 2352 bytes. The intervalsof the reading of the PCM data out of the DRAM 11A is 13.3 msec. Theread-out PCM data is supplied to the D/A converter 22.

Thus, the processing is controlled by alternately switching over twobanks of each of the DRAMs 11A, 11B and 11C, and synchronizing thetimings of switching over the banks among the DRAMs 11A, 11B and 11C.The synchronous control is performed, as described above, through flagcontrol with one flag allocated to each task. As a result, the readingof data out of the CD 55 for the high-rate encoding, see FIG. 40, andthe reading of data out of the CD 55 for the ordinary playback, see FIG.41, for example, can be controlled in a manner out of interference witheach other.

FIG. 42 is a functional block diagram representing the case where thetasks shown in FIG. 34 are allocated to respective components of themusic server according to the first modification of the embodimentdescribed above with reference to FIG. 27. Note that, in FIG. 42,components in common with those in FIG. 27 are denoted by the samenumerals and a detailed description thereof is omitted here.

In this example, as with the above, the DRAMs 401A, 401B and 401C inFIG. 27 are each made up of two banks, that is, banks D00 and D01, banksD10 and D11, and banks D20 and D21. Additionally, the DRAM 401D in FIG.27 is also made up of two banks, that is, banks D30 and D31.

Further, in the example of FIG. 42, the processing by the compressiondecoder 21 is added to the example of FIG. 35, and therefore a taskHdReadTask and another task CoderWriteTask are added correspondingly.These tasks HdReadTask and CoderWriteTask are created in response to astartup request from the above-described task StorageTask. The priorityorders of the task HdReadTask and the task CoderWriteTask are assignedto 50 and 60, respectively.

The timing of reading the compressed audio data out of the HDD 10, thetiming of writing the compressed audio data in the DRAM 401C, the timingof reading the compressed audio data out of the DRAM 401C, and thetiming of writing the compressed audio data in the compression decoder21 are controlled by those tasks HdReadTask and CoderWriteTask in synchwith the other tasks similarly to the above-described example of FIG.35.

FIG. 43 is a functional block diagram representing the case where thetasks shown in FIG. 35 are allocated to respective components of themusic server according to the second modification of the embodimentdescribed above with reference to FIG. 28. Note that, in FIG. 43,components in common with those in FIG. 28 are denoted by the samenumerals and a detailed description thereof is omitted here. Also, inFIG. 43, the DRAMs 402A, 402B and 402C in FIG. 28 are shown as clearlyindicating that each DRAM is made up of two banks, that is, banks D00and D01, banks D10 and D11, and banks D20 and D21.

In the example of FIG. 43, the PCM data read out of the DRAM 402B issupplied to both the D/A converter 22 and the ATRAC encoder 12. To thisend, two tasks CoderWriteTask2 and PcmWriteTask must be executed inparallel on the output side of the DRAM 402B.

Further, in the example of FIG. 43, the processing by the compressiondecoder (MP3 decoder 403) is added to the example of FIG. 35, andtherefore a task CoderReadTask2 and a task CoderWriteTask2 are addedcorrespondingly.

A, B, and C of FIG. 44 are flowcharts showing one example of theprocessing executed by a dotted area in FIG. 43, that is, by the taskCoderReadTask2 on the input side of the DRAM 402B, and the taskCoderWriteTask2 and the task PcmWriteTask both on the output side of theDRAM 402B. A shows the processing executed by the task CoderReadTask2, Bshows the processing executed by the task CoderWriteTask2, and C showsthe processing executed by the task PcmWriteTask, respectively. Notethat, in A, B, and C of FIG. 44 steps S175, S177, S178, S179, S181, S191and S192 represent the processing executed by the real time OS.

In A of FIG. 44, when the task CoderReadTask2 receives a startup requestfrom the task StorageTask, the status flag indicating the state of theDRAM 402B is initialized in step S170 such that one bank D10 and theother bank D11 of the DRAM 402B are each set to the Empty stateindicating the relevant bank being empty.

After the status flags of the banks of the DRAM 402B have beeninitialized, a startup request is issued from the task CoderReadTask2 tothe task CoderWriteTask2 in step S171. In response to the startuprequest, the processing shown in the flowchart of FIG. 44C is started.Further, a startup request is issued from the task CoderReadTask2 to thetask PcmWriteTask in step S172. In response to the startup request, theprocessing shown in flowchart B is started. The flowcharts B and C willbe described later.

Then, in A of FIG. 44, it is determined in the next step S173 whetherthe PCM data has been completely read out of the CD 55. If the readingof the PCM data is completed, the process flow goes to step S178 wherethe CPU waits for a notice of end from the task CoderWriteTask. Then, innext step S179, the CPU further waits for a notice of end from the taskPcmWriteTask. Whether the PCM data has been completely read out of theCD 55 is determined, for example, by the CPU 8 monitoring the operationof the CD 55. A determination result is noticed to the real time OS.

On the other hand, if it is determined in step S173 that the PCM datahas not been completely read out of the CD 55, the process flow goes tostep S174 where the bank of the DRAM 402B is set to the bank D10. Withthe bank setting in step S174, the two banks are alternately switchedover such that the selected bank is changed in the order of bank D10,bank D11, bank D10, . . . whenever the processing started from step S173is looped. The PCM data read out of the CD 55 through the taskCoderReadTask2 is accumulated in the bank of the DRAM 402B set in stepS174.

In next step S175, the command waitFlag is issued by the taskCoderReadTask2, and the real time OS waits for until the bank (assumedto be D10) of the DRAM 402B set in step S174 comes to the Empty state.If the bank D10 comes to the Empty state, the process flow goes to stepS176.

In step S176, the PCM data is read out of the CD 55 in amountcorresponding to the capacity of the bank (bank D10) of the DRAM 402Bset in step S174. The read-out PCM data is DMA-transferred to the bankD10 of the DRAM 402B and written in the bank D10.

When the predetermined amount of the PCM data is written in the bankD10, the task CoderReadTask2 issues the command setFlag in next stepS177, whereby the status flag of the bank D10 is set to Full. After thecompletion of the flag setting, the process flow returns to step S173.

On the other hand, the processing shown in flowchart B is startedfollowing the processing in above-described step S172. Morespecifically, when the startup request is issued in step S171 to thetask CoderReadTask2, the bank of the DRAM 402B is set to the bank D10 instep 180. With the bank setting in step S180, the two banks arealternately switched over such that the selected bank is changed in theorder of bank D10, bank D11, bank D10, . . . whenever the processing islooped from step S184 described later.

In the next step S181, the command waitFlag is issued by the taskCoderReadTask2, and the real time OS waits for until the bank (assumedto be D10) of the DRAM 402B set in step S180 comes to the Full state.Stated otherwise, in step S181, the CPU waits for the end of theprocessing of step S177. If the bank D10 comes to the Full state, theprocess flow goes to step S182.

In step S182, the PCM data is read out of the bank (bank D10) of theDRAM 402B set in step S180 in amount corresponding to the capacity ofthe bank D10. The read-out PCM data is DMA-transferred to thecompression encoder 12 and written in, for example, a processing memoryfor the compression encoder 12.

In the above-described flowchart B of FIG. 37, after the PCM data hasbeen written in the compression encoder in step S122 corresponding tostep S182 shown in the flowchart B of FIG. 44, the relevant bank is setto the Empty state by the command setFlag in next step S23. By contrast,in the flowchart B of FIG. 44, after the PCM data has been written inthe ATRAC encoder 12 in step S182, the processing of step S183corresponding to above-described step S123 is not executed. In otherwords, the relevant bank is not set to the Empty state.

Accordingly, after the PCM data has been written in the ATRAC encoder 12in step S182, the process flow goes to step S184, as a next step, whereit is determined whether the PCM data has been completely read out ofthe CD 55. If it is determined that the PCM data has not been completelyread out of the CD 55, the process flow returns to step S180.

On the other hand, if it is determined in step S184 that the PCM datahas been completely read out of the CD 55, a notice of end is passedfrom the task CoderWriteTask2 to the task CoderReadTask2, whereby asequence of the processing shown at B in FIG. 44 is ended. Then, thenotice of end from the task CoderWriteTask2 is received by the taskCoderReadTask2 in above step S178, and the process flow of A in FIG. 44goes to step S179.

Further, the processing shown in the flowchart C of FIG. 44 is startedfollowing the processing in above-described step S171. Morespecifically, when the startup request is issued in step S171 to thetask PcmWriteTask, the bank of the DRAM 402B is set to the bank D10 instep 190. With the bank setting in step S190, the two banks arealternately switched over such that the selected bank is changed in theorder of bank D10, bank D11, bank D10, . . . whenever the processing islooped from step S194 described later.

In next step S191, the command waitFlag is issued by the taskPcmWriteTask, and-the real time OS waits for until the bank (assumed tobe D10) of the DRAM 402B set in step S190 comes to the Full state.Stated otherwise, in step S191, the CPU waits for the end of theprocessing of step S177. If the bank D10 comes to the Full state, theprocess flow goes to step S192.

In step S192, the PCM data is read out of the bank (bank D10) of theDRAM 402B set in step S190 in amount corresponding to the capacity ofthe bank D10. The read-out PCM data is DMA-transferred to the D/Aconverter 22 and written in, for example, a processing memory for theD/A converter 22.

If the predetermined amount of the PCM data is read out of the bank D10of the DRAM 402B in step S192, the process flow goes to next step S193.In step S193, the command setFlag is issued by the task PcmWriteTask andthe status flag of the bank D10 is set to the Empty state.

After the end of the flag setting, the process flow goes to step S194where it is determined whether the playback of the CD 55 is completed.If it is determined that the playback of the CD 55 is not completed, theprocess flow returns to step S190.

On the other hand, if it is determined in step S194 that the playback ofthe CD 55 is completed, a notice of end is passed from the taskPcmWriteTask to the task CdReadTask2, whereby a sequence of theprocessing shown at C in FIG. 44 is ended. Then, if the notice of endfrom the task PcmWriteTask is received by the task CoderReadTask2 inabove step S179, a sequence of the processing shown in FIG. 44 is ended.

The third and fourth modifications of the embodiment, described abovewith reference to FIGS. 29 and 30, can also be controlled throughprocessing basically similar to that employed in the embodiment and thefirst and second modifications of the embodiment, and hence a detaileddescription thereof is omitted here.

FIG. 45 is a functional block diagram representing the case where thetasks shown in FIG. 35 are allocated to respective components of themusic server according to the fifth modification of the embodimentdescribed above with reference to FIG. 31. Note that, in FIG. 45,components in common with those in FIG. 31 are denoted by the samenumerals and a detailed description thereof is omitted here. Also, inFIG. 45, the DRAMs 421A, 421B and 421C in FIG. 31 are shown as clearlyindicating that each DRAM is made up of two banks, i.e., banks D00 andD01, banks D10 and D11, and banks D20 and D21.

In the fifth modification, signal paths are arranged such that pluraltypes of processing can be selectively performed, and the DRAMs 421A,421B and 421C can effect plural types of functions in parallel.Accordingly, a task is also selectively started up from among aplurality of tasks in accordance with the control timing. For example,on the input side of the DRAM 421B, one of the task CoderWriteTask andthe task CoderWriteTask2 is selectively started up. Also, on the outputside of the DRAM 421B, one of the task HdWriteTask and the taskPcmWriteTask is selectively started up. The necessary task isselectively started up by the task StorageTask case by case undercontrol of the real time OS.

According to the present invention, as described above, the user canlisten to sounds reproduced from a CD while audio data recorded on theCD is written in an HDD at a high data rate. Therefore, the user canutilize time efficiently.

Also, according to the present invention, the contents of a CD, fromwhich audio data is written in an HDD, can be confirmed during thewriting, thus keeping the user free from worry.

1. An apparatus for writing and reproducing data, comprising: processingmeans for processing inputted data and for producing processed data;storage means for storing said processed data in a storage medium;decompression means for decompressing processed data stored in saidstorage medium and for producing decompressed data; reproducing meansfor reproducing said decompressed data; control means for controllingsaid storage means to store said processed data in said storage mediumduring reproducing of said decompressed data by said reproducing means;reading out means for reading out data stored in said storage mediumtherefrom at a predetermined reading out data rate; and a buffer memoryconfigured to temporarily store said data read out from said storagemedium, wherein said control means controls said storage means to writesaid processed data at a faster writing data rate than saidpredetermined reading out data rate and to stop writing of saidprocessed data in said storage medium by said storage means, and saidcontrol means controls said reading out means to read out said storeddata from said storage medium when an amount of said stored data in saidbuffer memory is less than a predetermined amount.
 2. An apparatus forwriting and reproducing data, comprising: converting means forconverting inputted data of a first compression format into converteddata of a second compression format; outputting means for outputtingsaid converted data of said second compression format converted by saidconverting means; reproducing means for reproducing data correspondingto said converted data of said second compression format; control meansfor controlling said outputting means to output said converted data ofsaid second compression format during reproducing of said data by saidreproducing means; storage means for storing said converted data of saidsecond compression format in a storage medium; decompression means fordecompressing said inputted data of said first compression format;compression means for compressing decompressed data into said converteddata of said second compression format; reading out means for readingout said converted data of said second compression format from saidstorage medium; second decompression means for decompressing read outconverted data of said second compression format; and a buffer memoryconfigured to store data read out from said storage medium temporarily,wherein said reproducing means reproduces data decompressed by saidsecond decompression means, and said control means controls said storagemeans to stop writing said converted data of said second compressionformat in said storage medium and controls said reading out means toread out stored data from said storage medium when an amount of saidstored data in said buffer memory is less than a predetermined amount.3. An apparatus for writing and reproducing data, comprising: processingmeans for processing inputted data according to a predeterminedrequirement; outputting means for outputting data supplied from saidprocessing means; storage means for storing data processed by saidprocessing means in a storage medium; reproducing means for reproducingsupplied data supplied by said storage medium; control means forcontrolling said outputting means to output said data supplied from saidprocessing means during reproducing of said supplied data by saidreproducing means; reading out means for reading out data stored in saidstorage medium at a predetermined reading out data rate; and a buffermemory configured to store said data read out from said storage mediumtemporarily, wherein said control means controls said reading out meansto read out data stored in said storage medium that is different fromsaid supplied data and controls said reproducing means to reproduce saidread out data during writing of said supplied data in said storagemedium by said storage means, said control means controls said storagemeans to write in said storage medium said supplied data at a fasterwriting data rate than said predetermined reading out data rate, andsaid control means controls said storage means to stop writing saidsupplied data in said storage medium and controls said reading out meansto read out said stored data from said storage medium when an amount ofsaid stored data in said buffer memory is less than a predeterminedamount.
 4. An apparatus configured to write and to reproduce data,comprising: a processing unit configured to process inputted data and toproduce processed data; a storage unit configured to store saidprocessed data in a storage medium; a decompression unit configured todecompress processed data stored in said storage medium and to producedecompressed data; a reproducing unit configured to reproduce saiddecompressed data; a control unit configured to control said storageunit to store said processed data in said storage medium duringreproducing of said decompressed data by said reproducing unit; areading out unit configured to read out data stored in said storagemedium therefrom at a predetermined reading out data rate; and a buffermemory configured to temporarily store said data read out from saidstorage medium, wherein said control unit controls said storage unit towrite said processed data at a faster writing data rate than saidpredetermined reading out data rate and to stop writing of saidprocessed data in said storage medium by said storage unit, and saidcontrol unit controls said reading out unit to read out said stored datafrom said storage medium when an amount of said stored data in saidbuffer memory is less than a predetermined amount.
 5. An apparatusconfigured to write and to reproduce data, comprising: a converting unitconfigured to convert inputted data of a first compression format intoconverted data of a second compression format; an outputting unitconfigured to output said converted data of said second compressionformat converted by said converting unit; a reproducing unit configuredto reproduce data corresponding to said converted data of said secondcompression format; a control unit configured to control said outputtingunit to output said converted data of said second compression formatduring reproducing of said data by said reproducing unit; a storage unitconfigured to store said converted data of said second compressionformat in a storage medium; a decompression unit configured todecompress said inputted data of said first compression format; acompression unit configured to compress decompressed data into saidconverted data of said second compression format; a reading out unitconfigured to read out said converted data of said second compressionformat from said storage medium; a second decompression unit configuredto decompress said read out converted data of said second compressionformat; and a buffer memory unit configured to store data read out fromsaid storage medium temporarily, wherein said reproducing unitreproduces data decompressed by said second decompression unit, and saidcontrol unit controls said storage unit to stop writing said converteddata of said second compression format in said storage medium andcontrols said reading out unit to read out stored data from said storagemedium when an amount of said stored data in said buffer memory is lessthan a predetermined amount.
 6. An apparatus configured to write and toreproduce data, comprising: a processing unit configured to processinputted data according to a predetermined requirement; an outputtingunit configured to output data supplied from said processing unit; astorage unit configured to store data processed by said processing unitin a storage medium; a reproducing unit configured to reproduce supplieddata supplied by said storage medium; a control unit configured tocontrol said outputting unit to output said data supplied from saidprocessing unit during reproducing of said supplied data by saidreproducing unit; a reading out unit configured to read out data storedin said storage medium at a predetermined reading out data rate; and abuffer memory configured to store said data read out from said storagemedium temporarily, wherein said control unit controls said reading outunit to read out data stored in said storage medium that is differentfrom said supplied data and controls said reproducing unit to reproducesaid read out data during writing of said supplied data in said storagemedium by said storage unit, said control unit controls said storageunit to write said supplied data in said storage medium at a fasterwriting data rate than said predetermined reading out data rate, andsaid control unit controls said storage unit to stop writing saidsupplied data in said storage medium and controls said reading out unitto read out said stored data from said storage medium when an amount ofsaid stored data in said buffer memory is less than a predeterminedamount.
 7. A method for writing and reproducing data1 comprising:processing inputted data and producing processed data; storing saidprocessed data in a storage medium; decompressing said processed datastored in said storage medium and producing decompressed data;reproducing data corresponding to said decompressed data; controllingsaid storing step to store said processed data in said storage mediumduring reproducing of said decompressed data by said reproducing step;reading out data stored in said storage medium therefrom at apredetermined reading out data rate; and temporarily storing said dataread out from said storage medium into a buffer memory, wherein saidcontrolling step controls said storing said processed data step to writesaid processed data at a faster writing data rate than saidpredetermined reading out data rate and to stop writing of saidprocessed data in said storage medium, and said controlling stepcontrols said reading out step to read out said stored data from saidstorage medium when an amount of said stored data in said buffer memoryis less than a predetermined amount.
 8. A method for writing andreproducing data, comprising converting inputted data of a firstcompression format into converted data of a second compression format;outputting said converted data of said second compression formatconverted by said converting step; reproducing said converted data ofsaid second compression format; controlling said outputting step tooutput said converted data of said second compression format duringreproducing of said data by said reproducing step; storing saidconverted data of said second compression format in a storage medium;decompressing said inputted data of said second compression format andcompressing decompressed data into said converted data of said secondcompression format; reading out said converted data of said secondcompression format from said storage medium; decompressing said read outconverted data of said second compression format; and storing said dataread out from said storage medium temporarily in a buffer memory,wherein said reproducing step reproduces data decompressed by saiddecompressing said read out converted data step, and said controllingstep controls said storing said converted data step to stop writing saidconverted data of said second compression format in said storage mediumand controls said reading out step to read out stored data from saidstorage medium when an amount of said stored data in said buffer memoryis less than a predetermined amount.
 9. A method for writing andreproducing data, comprising: processing inputted data according to apredetermined requirement; outputting data supplied from said processingstep; storing data processed by said processing step in a storagemedium; reproducing supplied data supplied by said storage medium:controlling said outputting step to output said data supplied from saidprocessing step during reproducing of said supplied data by saidreproducing step; reading out data stored in said storage medium at apredetermined reading out data rate; and storing said data read out fromsaid storage medium temporarily into a buffer memory, wherein saidcontrolling step controls said reading out step to read out data storedin said storage medium that is different from said supplied data andcontrols said reproducing step to reproduce said read out data duringwriting of said supplied data in said storage medium by said storingdata processed step, said controlling step controls said storing dataprocessed step to write said supplied data in said storage medium at afaster writing data rate than said predetermined reading out data rate,and said controlling step controls said storing data processed step tostop writing said supplied data in said storage medium and controls saidreading out step to read out said stored data from said storage mediumwhen an amount of said stored data in said buffer memory is less than apredetermined amount.